This sentence discusses a condition that is contrary to fact (IF Jerry were in my position, which he is not), and thus uses the subjunctive mood. The subjunctive mood is used to express a wish, suggestion, condition, condition contrary to fact, or command. Because the sentence requires the subjunctive mood, the correct version reads: "Jerry said if he were in my position, he would do the same thing."

The sentence is correct because we change "was" to "were" following a noun in situations in which the statement communicates something contrary to fact or highly unlikely.

The example sentence expresses a hypothetical condition that is contrary to fact ("I," by definition, am not "you"), and therefore needs to be expressed using verbs in the subjunctive mood. "If" is a usually a good indication that a sentence will be in the subjunctive mood. In the subjunctive, "were" should be used instead of "was." "If I were you, I would leave that job immediately."

In the original sentence, the verb "knows" is in the incorrect mood—the indicative. Because of the word "that", we know the sentence contains an order, which means that we must change the verb to the subjunctive mood ("know").

This sentence is an example of the present subjunctive, which is most commonly used in English to express hypothetical situations, wishes, and desires. The correct long form of the sentence is “if you were to choose that restaurant,” and “were you to choose that restaurant” is simply an inversion and shortening of the long form. (“Were you to have chosen that restaurant” is the past subjunctive, which doesn’t match the future conditional form of the second half of the sentence.)

This sentence is a rare use of the subjunctive mood, a verb mood that is used to indicate a hypothetical state or a statement contrary to reality. The subjunctive verb does not use the otherwise more appropriate verb tense "was," as it is indicating a desire of something not real and should use "were." "If I were a betting man" is the only answer choice that uses the correct verb form.

When indicating a desire or proclamation, the subjunctive form of a verb—in this case, "be" instead of the usual indicative "is"—should be used.

Sticking "you" in this sentence is unnecessary with the phrase's imperative mood and the implied subject of "you" in the first part of the sentence, which creates a lack of parallel structure. "You" should be taken out of the underlined portion of the sentence to fix these problems. As only one answer choice makes this change, the correct answer is "and wait for them to be completely finished before returning."

This sentence will try to trick you into using the subjunctive mood, but remember that the subjunctive is only used to describe hypothetical situations and dreams. Because the character actually did jump into the murky lake, the correct mood is simply the past indicative: “He said he wouldn’t have jumped into the murky lake if someone else hadn’t jumped before him.”

The choices that include the pronoun "it" are clearly wrong because there is no noun preceding the word "it" that can be referenced. This question involves a dangling modifier. What is touching on those subjects? The book. The book should therefore come after the comma. Eliminate answers that do not have this structure. "Must" is clearly awkward. "Shall" is not usually used in the third person. It is usually used in the first person. It is used to make suggestions or to give offers of help, for example, "shall we go to the beach" and "shall I help you with those bags". The correct choice implements the simple structure "the book will tell".