This sentence is correct as it is. Here, the statement in quotation marks is a counterfactual statement. This means that it talks about something that isn't actually the case in reality. The narrator is thinking about what might happen if she lavished care on her plants, but in reality, she is not lavishing care on her plants. Counterfactual statements use the verbs in the subjunctive. “Were” is the subjunctive form of the English verb “to be” (or “am,” in this sentence).

This sentence expresses a counterfactual statement, so it needs verbs in the subjunctive mood. “Could” can be thought of as a past subjunctive form of the verb “can,” so there is no problem with the first part of the sentence; however, the verb in the second part of the sentence, “will need,” is in the indicative mood, not the subjunctive. To correct this, we have to change “will need” to its past subjunctive form, “would need.”

In English, the subjunctive mood of verbs is often used after certain expressions like “it is necessary that” or “it is important that.” The subjunctive is used to talk about wishes, desires, or thoughts about things that aren't actually the case. In this sentence, the expression “it is necessary that” introduces a phrase that must use the subjunctive, because it expresses something that the boss desires. So, we have to change the verb “are,” which is in the indicative mood, to its subjunctive form, “be.”

In this sentence, the phrase “he be the most promising researcher” uses the subjunctive “be"; however, in English, the subjunctive should only be used in a phrase that talks about a desire, wish, or counterfactual statement—not when the phrase reports true facts (or what the person saying the phrase thinks are true facts about the world). In the view of the person who wrote the letter, the young scientist is currently the most promising researcher. So, we should use the verb “is,” which is in the indicative mood. “Is” is also right because it is in the present tense, like the rest of the sentence.

The phrase “Marie's tutor recommended that Marie look” contains the present-tense subjunctive verb “look,” and it is right as it is. This is because the subjunctive mood is used after expressions like “recommend that” and “advise that” to express someone's wishes and desires. “Looks,” “looked,” and “will look” are all in the indicative mood, so they are not correct.

This sentence expresses a counterfactual statement, or a statement that does not match the way things are in reality. It is not actually the case that the narrator is the person she is talking to. Counterfactual sentences use subjunctive verbs. So, we need to change the verb “was,” which is in the indicative, to its subjunctive form, “were.”

Here, the words “requests that” introduce a phrase that requires the subjunctive mood. The subjunctive is used after phrases like “requires that” or “requests that” to express the wishes and desires of the person doing the requesting. In this sentence, the verb “stands” is in the indicative mood, but it should be changed to its subjunctive form, “stand.”

Here, the words “requires that” introduce a phrase that requires the subjunctive mood. The subjunctive is used after phrases like “requires that” or “requests that” to express the wishes and desires of the person doing the requesting. In this sentence, the verb “studies” is in the indicative mood, but it should be changed to its subjunctive form, “study.”

This sentence uses the subjunctive verb “be” in the phrase “he be committed”; however, in the way the sentence is written, this phrase was spoken by Bob's mother, who believes it to be true. It's not part of a phrase that expresses any kind of wish, desire, or counterfactual statement. To Bob's mother, the idea that Bob is committed to studying for two hours is a true fact about the world. Therefore, this fact should be expressed using the indicative mood, not the subjunctive. We should change the subjunctive verb “be” to its indicative form, “is.”

The second part of this sentence expresses a counterfactual statement. It is describing what might have happened if the weather had been nice; however, we know that in reality, it was raining. Since counterfactual statements use the subjunctive mood, we need to change the indicative verb “go” to a past-tense subjunctive form, “would have gone.” We know that the subjunctive form has to be in the past tense because the conditional is talking about what might have happened in the past.