The best choice is "staggering." Since the article used in this sentence is "a" instead of "an," we know that the next work in the sentence has to start with a consonant and not a vowel, which eliminates "amazing" and "enormous" even though both of these words make sense logically. The other choice, "distressing" implies that it makes you upset, which does not make sense in this context. The best choice is "staggering" which means large and overwhelming.

Here, a "call" is a thing made with a phone, not the direct verb of the clause. The context that is important here is the phone. "Call" is the only noun listed that is related to a telephone.

The correct answer is "exam." We know from the sentence that the subject was trying to pass something but failed. The nouns "experiment" and "estimation" are not things that can be passed. An "attempt" is a try, and although the subject did try to pass the exam, he was not successful. The best answer is "exam."

The best choice is "disruption;" a word meaning a disturbance or commotion, which is what would occur if someone dropped plates in a quiet restaurant. "Tranquility," meaning an environment of calm, is the opposite of what would happen. "Separation" is a state of being moved apart, as is "break," so both of these choices do not make sense in this sentence. The best choice is "disruption."

The possessive pronoun their indicates that a noun is needed, so the only two options are progress and progression. Progression is a noun describing the act of progressing, whereas progress (when used as a noun and not a verb) can be used to measure space or distance.  

The correct answer is "Doctors." This sentence requires a plural noun to agree with the plural pronoun "their" later in the sentence. The other answer choices are all singular, which is why the only answer choice that fits grammatically is "doctors."

The correct answer is "shoes." This answer is correct because it is plural. We know that we need a plural subject because it has to agree with the plural verb, "were." "Shirt," "shoe," and "backpack" are all singular, so they do not agree with the plural verb "were." That is why the best choice is "shoes."

The correct answer is "man." We know that we need a singular noun, and also a male because the sentence states "his shirt." The subject of the sentence must agree with the pronoun. Since the other options are plural and/or feminine, they are incorrect.

The correct answer is "cats." This is a plural noun, and we know we need a plural noun because of the plural verb "were." The other options are singular, so they would be incorrect if inserted into this sentence. Therefore, the best choice is "cats."

The correct answer is "sailors." We know this is the correct answer because it is a plural noun. The subject of the sentence has to be plural because the verb "have to wear" is in plural form. The other options are singular, so they would be grammatically incorrect in this sentence. The best choice is "sailors."