TOEFL Practice Test #8 — Questions and Answers

Question 1: ______ aluminum is exposed to oxygen, a tough, invisible oxide forms, making it extremely corrosion-resistant.

No sooner than
Once (Correct answer)
So soon that
The sooner

Correct answer: Once

The word 'Once' correctly introduces a condition that, when met, triggers a specific outcome. The sentence describes that *as soon as* or *when* aluminum is exposed to oxygen, a protective oxide layer forms. 'Once' establishes this immediate cause-and-effect relationship, making it the most appropriate conjunction to link the exposure to the resulting formation of the oxide.

Question 2: ______ the Silurian Period, there was significant radiation of rapacious fish equipped with bulky jaws.

When
Since
Until
During (Correct answer)

Correct answer: During

The preposition 'During' is used to indicate that an event or action takes place within a specific period of time. Here, the 'significant radiation of rapacious fish' occurred within the timeframe of 'the Silurian Period.' This makes 'During' the correct choice to specify when this evolutionary event happened.

Question 3: Sickle-cell anemia, which is a genetic defect, is caused by ____ that encourages a faulty form of hemoglobin.

mutant a certain allele
a certain mutant allele (Correct answer)
a mutant allele certain
an allele certain mutant

Correct answer: a certain mutant allele

This question tests the correct order of adjectives before a noun. The standard English adjective order is typically article + opinion/size/age/shape/color/origin/material + noun. In this case, 'a' is the article, 'certain' and 'mutant' are descriptive adjectives, and 'allele' is the noun. Therefore, 'a certain mutant allele' follows the correct grammatical structure.

Question 4: Mary McLeod Bethune, a leading African-American _____, as a child attended the local free school.

educator who
educator (Correct answer)
educator she
whose education

Correct answer: educator

The sentence uses an appositive phrase to provide additional information about Mary McLeod Bethune. An appositive is a noun or noun phrase that renames or clarifies another noun right beside it. 'Educator' is the correct noun form to function as an appositive, describing her profession without introducing unnecessary clauses or pronouns.

Question 5: Beryllium is used as a bonding agent for nuclear fuel elements ____ toughness and excellent resistance to heat.

although its
it is when
that its
because of its (Correct answer)

Correct answer: because of its

The phrase 'because of its' correctly introduces a reason or cause, followed by a noun phrase. In this sentence, beryllium is used as a bonding agent *because of* its inherent qualities of 'toughness and excellent resistance to heat.' This construction clearly explains the justification for its use.

Question 6: After the wine is clarified, it _____ in wooden kegs or stainless steel tanks to age.

keeps
is kept (Correct answer)
had been kept
keeping

Correct answer: is kept

The sentence describes a general process where wine is the recipient of the action 'keep.' Therefore, the passive voice is required, as the wine does not perform the action itself but is acted upon. 'Is kept' is the correct present tense passive form, indicating a routine or standard procedure.

Question 7: Amphibians thrive in humid areas, nevertheless, their habitats are constantly decreased __________ new construction.

because
due to (Correct answer)
for
since

Correct answer: due to

The phrase 'due to' is a prepositional phrase that means 'because of' and is used to introduce the reason or cause for something. In this sentence, the decrease in amphibian habitats is attributed to 'new construction.' 'Due to' correctly links the cause (new construction) to the effect (decreased habitats).

Question 8: Natural rubber is an exceptionally useful raw material because it retains air, keeps out moisture, and does not ______ electricity.

conduct (Correct answer)
conductor
conducting

Correct answer: conduct

The sentence uses parallel structure to list the properties of natural rubber: 'retains air, keeps out moisture, and does not ______ electricity.' For parallelism, the verb following 'does not' must be in its base form, just like 'retains' and 'keeps.' 'Conduct' is the correct base form of the verb, maintaining consistency in the list.

Question 9: After a rainfall in the desert, the water _____ in the playas either vaporizes or trickles down into the earth.

was collected
has collected
collected (Correct answer)
to collect

Correct answer: collected

The word 'collected' functions as a past participle, forming a reduced relative clause that modifies 'water.' It implies 'the water *which was collected* in the playas.' This construction is grammatically correct and concisely describes the state of the water after a rainfall.

Question 10: Select the right response. Sunspots are by far the most obvious flaws on the Sun's surface.

are (Correct answer)
That are
the
in the

Correct answer: are

The subject of the sentence is 'Sunspots,' which is plural. Therefore, the verb must agree with the plural subject. 'Are' is the correct plural form of the verb 'to be,' making the original sentence grammatically sound with proper subject-verb agreement.

Question 11: Select the right response. Alaska is home to between 30,000 and 40,000 brown bears, often known as grizzlies, which makes up nearly all of the brown bears in the United States.

Are resident
reside
Live (Correct answer)
inhabit

Correct answer: Live

The verb 'live' is the most natural and common choice to describe animals inhabiting a particular place. The sentence states that Alaska 'is home to' brown bears, and 'live' directly conveys the idea of their presence and habitation in that region. Other options like 'are resident' are grammatically awkward in this context.

Question 12: Select the right response. The difficulties of reconciling a pan-European goal with the national interests of 25 distinct countries make the integration process slow, difficult, and occasionally polarizing.

causes
Have made (Correct answer)
Often affect
Resulting in

Correct answer: Have made

The subject of the sentence is 'The difficulties,' which is a plural noun. Therefore, the verb must agree with this plural subject. 'Have made' is the correct plural form for the present perfect tense, indicating that these difficulties have caused the integration process to be slow, difficult, and polarizing up to the present.

Question 13: The United Nations has banned international trade in the 20 or so different species of sturgeon since 1998 as a result of a sharp increase in poaching.

is controlled
Has been regulated (Correct answer)
Has been regulated
Has been promoted

Correct answer: Has been regulated

The sentence describes an action that began in the past ('since 1998') and continues to have relevance or effect in the present. The phrase 'has been regulated' uses the present perfect passive voice, which is appropriate for an action that started in the past and continues or has an ongoing result. The trade is being acted upon, hence the passive voice.

Question 14: There are 4 underlined sections in the text below. Select the one which is wrong. Crushed ice is use to cool drinks, and is often applied to injuries where there is swelling, to remove excess heat generated in the tissues.

use (Correct answer)
is often
When there is
generated

Correct answer: use

The error is in the word 'use.' In the passive voice construction 'Crushed ice is ______ to cool drinks,' the past participle form of the verb is required. Therefore, 'use' should be 'used,' as in 'Crushed ice is used to cool drinks.' The ice is the object of the action, not the performer.

Question 15: There are 4 underlined sections in the text below. Select the one which is wrong.Japan's latitudinal spread, ranging from subtropical in the south to sub-arctic in the north, makes that a wide diversity of flora and fauna

Latitudinal spread
Makes that (Correct answer)
Subtropical
Wide diversity

Correct answer: Makes that

The phrase 'makes that a wide diversity' is grammatically incorrect and awkward. A more natural and idiomatic construction to express cause or result would be 'makes for a wide diversity' or 'results in a wide diversity.' 'Makes that' is not a standard English idiom in this context.

Question 16: There are 4 underlined sections in the text below. Select the one which is wrong.Greece's achievement in the 2004 Olympics raise anew the question of whetherAthens should be the permanent home of the Games.

Achievement in the
Raise anew (Correct answer)
Whether
Should be

Correct answer: Raise anew

The subject of the sentence is 'Greece's achievement,' which is singular. The verb must agree with this singular subject. Therefore, 'raise anew' should be 'raises anew' to maintain subject-verb agreement in the present tense, indicating that the achievement continues to bring up the question.

Question 17: Choose the correct answerFood is, after all, an important part of Chinese culture and mission controllers say it is important _____ China's space pioneers do not go hungry.

To ensure that (Correct answer)
So that
Make sure
that food is provided for

Correct answer: To ensure that

The phrase 'it is important to ensure that' is the correct and idiomatic way to express the necessity of making certain something happens. 'To ensure that' introduces a subordinate clause explaining what needs to be guaranteed, fitting the context of mission controllers wanting to prevent hunger among space pioneers.

Question 18: Choose the correct answerThe 2000 Census showed that married couples _____ half of the 2 million households in the state, and 46 percent of those couples had children under roof.

and made up
Made up (Correct answer)
To make up
Which they made up

Correct answer: Made up

The sentence refers to information from 'The 2000 Census,' indicating a past event. Therefore, the verb describing what married couples did in 2000 must be in the simple past tense. 'Made up' correctly conveys a completed action in the past, aligning with the historical context provided by the census data.

TOEFL Practice Test #8

______ aluminum is exposed to oxygen, a tough, invisible oxide forms, making it extremely corrosion-resistant.