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Free TOEFL Practice :: Structure 171-180 ANSWERS
 

Answers: #171-180

All explanations were written by Erin Billy, specifically for the areas of difficulty of TestMagic students.

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171.

When iron is exposed to water, oxidizes, a process commonly known as rusting.

exposed
to
oxidizes

  • Correction: it oxidizes

  • Level of Difficulty: Medium

  • Magic explanation: This one is easy to explain and to understand. We simply need a main subject here. If you missed this one, it was probably a careless mistake. Remember, we can raise our TOEFL scores more quickly if we don't miss the easy questions!!

known as

 

172.

Somewhat analogous to the Chinese system of writing in difficulty for non-native speakers to learn and loosely based on the Chinese system of writing the Japanese system of writing known as Kanji.

to
difficulty
loosely based
the

  • Correction: is the

  • Level of Difficulty: HARD!!

  • Magic explanation: Whew! This is a hard question for a couple of reasons. First, the sentence is long and has a lot of extra phrases. Second, we have inversion here. The main subject is "the Japanese system of writing," so, we need a main verb, "is."

 

173.

 ______ big cats, housecats have polyphasic sleeping patterns; that, is they take several naps a day.

They are like

  • Magic explanation: If we choose this answer, we will have two main sentences with no conjunction between them. Be careful of this mistake--it is one of the most common ones on the TOEFL!!

Like

  • Level of Difficulty: Easy

  • Magic explanation: First, we should notice here that we have a complete main sentence already. The only thing we have to worry about is using another word or phrase with "big cats." If we use the preposition "like," then "big cats" becomes the object of the preposition.

It is the

  • Magic explanation: If we choose this answer, we will have two main sentences with no conjunction between them. Be careful of this mistake--it is one of the most common ones on the TOEFL!!

The

  • Magic explanation: If we choose this answer, we will essentially have two main subjects here, or what we often call a "double subject."

 

174.

It was as a direct result of the widespread implementation electricity that the US had a source of light other than gas lights.

It was
result of
implementation

  • Correction: implementation of

  • Level of Difficulty: medium

  • Magic explanation: First, we should notice that we have a preposition here, "of." "implementation" is the object of this preposition. A preposition can NEVER have two objects, so we should use another preposition with the noun "electricity."

a source of

 

175.

 ______ many communications companies are now able to offer radio and television broadcasts over the Internet.

Advanced technology has enabled

  • Magic explanation: This answer choice is wrong for two reasons. First, "enabled" needs an object. Second, even if we have an object for "enabled," we would end up with two complete sentences with no conjunction between them. As I stated above, this is a big no-no and is a very common mistake.

Introducing advanced technology and

  • Magic explanation: This answer choice is wrong because we need another noun to be parallel with "technology." If we had another noun, for example "new methods of storing data," then this answer choice would be correct.

Because the introduction of advanced technology

  • Magic explanation: This answer choice is wrong because we need a subordinate verb after the subordinating conjunction "because."

With the introduction of advanced technology

  • Level of Difficulty: Medium

  • Magic explanation: First, we should notice that we have a complete main sentence here and that nothing is missing from the sentence as it is written. When nothing is missing from the sentence, we should add something that is both optional and complete. This answer choice is the only one that meets these criteria--it is a prepositional phrase, and prepositional phrases are almost always optional in the sentence.

 

176.

While it is actually a planet, Venus is often mistaken a star in the night sky.

While it
a planet
mistaken

  • Correction: mistaken for

  • Level of Difficulty: Medium

  • Magic explanation: The correct idiom to use here is "to mistake x for y" (in the active voice), or "x is mistaken for y" (in the passive voice).

the night

 

177.

______ its area of defense, a fort should be built on an elevation and with some sort of natural feature of the landscape to obstruct direct access to the fort.

To better protect

  • Level of Difficulty: Hard

  • Magic explanation: We should use the infinitive of purpose here to explain how or why something is done.

Protecting better

  • Magic explanation: If you missed this question, you probably chose this answer. We cannot choose this answer choice because "protecting" modifies "fort" in this sentence either as an adjective phrase or an adverbial phrase (we have some ambiguity in this construction). Since the main sentence is making recommendations about how to build a fort, we should use the infinitive of purpose, not the participial form.

For the better of

  • Magic explanation: The easiest way to explain this one is simply to point out that "better" cannot be a noun.

It is better for

  • Magic explanation: Again, this answer choice would give us two main clauses with no conjunction between them.

 

178.

In 2000 William Jefferson Clinton entered his last year office as President of the United States.

In 2000
entered
office

  • Correction: of office

  • Level of Difficulty: Medium

  • Magic explanation: The verb "entered" can have only one object. In this case, the object of "entered" is "year," leaving us with an extra noun, "office." Since "entered" cannot have two objects, we should use a preposition to make "office" the object of the preposition.

as President

 

179.

It was ______ the Industrial Revolution that the United States was able to increase productivity through mechanization.

when

  • Magic explanation: If we choose this answer choice, we would be missing a subordinate verb. In other words, we would have to have a complete subordinate clause, something like this: …when the Industrial Revolution… DID something.

at the time

  • Magic explanation: The easiest way to explain this one is to point out that we would need to say "at the time of."

during

  • Level of Difficulty: Medium

  • Magic explanation: We essentially need a preposition (or some other word) here for the noun phrase Industrial Revolution.

because

  • Magic explanation: If we choose this answer choice, we would be missing a subordinate verb. In other words, we would have to have a complete subordinate clause, something like this: …because the Industrial Revolution… DID something.

 

180.

______ Einstein was able to come up with a theory that has yet to be disproved.

Other scientists

  • Magic explanation: This answer choice would give us a double subject, a big no-no on the TOEFL.

Similar to other scientists

  • Level of Difficulty: Medium

  • Magic explanation: This is a typical TOEFL question. First, we should notice that we have a complete main sentence here and that nothing is missing from the sentence as it is written. When nothing is missing from the sentence, we should add something that is both optional and complete. This answer choice, and the last one, are the only ones that meet these criteria.

Just as other scientists

To be a scientist

  • Magic explanation: This choice is wrong because we should not use the infinitive of purpose here; i.e., the main clause does not explain HOW or WHY Einstein was a scientist.

 

 

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