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Sentence Correction: Parts of Speech - Articles

Nobody knows the exact amount of undocumented immigrants living in the USA, and estimates vary substantially.

You're right!

This answer choice corrects the original article mistake by changing amount to number - immigrants is a count noun, which requires the use of number

[[snippet]]

Incorrect.

This answer choice is grammatically incorrect: the article the amount of can describe only non-count nouns whereas the noun immigrants is a count noun.

[[snippet]]

Incorrect.

This answer choice repeats the original mistake: the article the amount of can describe only non-count nouns whereas the noun immigrants is a count noun.

[[snippet]]

In addition, the omission of the word illegal changes the meaning of the original sentence.

Incorrect.

While this answer choice corrects the original article mistake, it does not stop there and makes another change: deleting the word undocumented. This changes the meaning of the original sentence.

Incorrect.

While this answer choice corrects the original article mistake, it does not stop there and makes another change: replacing the single word Nobody with the two-word phrase No one. This creates redundancy.

In addition, using the plural form numbers is illogical. There is a single number of undocumented immigrants. We may not know what this number is, but this does not change the fact that it is a certain single number.

Nobody knows the exact amount of undocumented immigrants living in the USA, and
Nobody knows the exact amount of immigrants living in the USA, and
Nobody knows the exact number of immigrants living in the USA, and
Nobody knows the exact number of undocumented immigrants living in the USA, and
No one knows the exact numbers of undocumented immigrants living in the USA, and