In the sentence above, because the initial noun used is "candidates'" is later referred to by a singular phrase "that interviewee."  Since there is no option to replace the singular noun, we know that the candidate in the inititial sentence is meant to be a singular candidate, and as it is written, it's a plural candidate.  The best way to correct the underlined portion of the sentence above is: "the candidate's personality."

In the sentence above, because the initial noun used is "men" we know that we are dealing with a group of men. Later in the sentence, the corresponding noun "assistant" should be plural. The best way to correct the underlined portion of the sentence above is: "grateful to be the assistants to such a great man."

In the sentence above, because the initial noun used is "stars" we know that we are dealing with a group of stars.  Therefore, later in the sentence, the corresponding noun "player" should be plural.  The best way to correct the underlined portion of the sentence above is: "and were not the players they could have been thereafter."

Because the subject of the sentence ("children") is plural, it is presumed each child has their own basket and is looking for eggs. For this reason, the nouns "basket" and "egg" both need to be plural.

In the sentence above, because the initial noun used is "Paul" we know that we are dealing with an individual. Therefore, later in the sentence, the corresponding noun "knights" should be singular. The best way to correct the underlined portion of the sentence above is: "he was set on becoming a great knight."

Note that a colon is correctly used to join two independent clauses, where the second clause explains or clarifies the first.

In the sentence above, because the initial noun used is "amateurs" we know that we are dealing with a plural subject. Therefore, later in the sentence, the corresponding noun "performer" should be plural. The best way to correct the underlined portion of the sentence above is: "The amateurs wouldn't grow up to become great performers:"

Several amateurs cannot become one great performer (at least with how technology stands at this juncture of history).

In the sentence above, because the initial noun used is "charges" we know that we are dealing with a group of recruits. Therefore, later in the sentence, the corresponding noun "student" should be plural. The best way to correct the underlined portion of the sentence above is: "All four of Mariah's charges were excellent students,"

"All" is a pretty good indicator that a plural pronoun will need to be used.

This is a case in which we need to decide whether to use the word "which" or "that" to introduce the clause set apart from the rest of the sentence by commas. "That" is used to introduce information absolutely necessary to the sentence's meaning, whereas "which" is used to introduce information that would not change the sentence's meaning if it were removed from the sentence. Information that is not crucial to the sentence's meaning is usually set apart by commas.

In this case, the sentence "The last time it snowed, my dad lost control of his car and hit a tree" still makes sense, so we know that the information included between the commas isn't absolutely necessary to the sentence's meaning. Plus, the information in question is being set apart from the rest of the sentence by commas. So, we should use "which," and not "that."

Because the second independent clause contradicts the first in this compound sentence it is more correct to separate the two with the conjunction "but," not "and."

In standard English, when you use the phrase "not only" in a sentence, it should be followed by the phrase "but also." So, the correct answer is "When she went to the zoo, Lyndsey got to see not only tigers, but also polar bears, iguanas, and toucans."