Fill in: must(n't), (not) have to, ought to or need(n't) in the correct form.

Fill in: must(n't), (not) have to, ought to or need(n't) in the correct form.

To solve this question, we need to understand the meaning and usage of each of these modal verbs.

1. "Must" is used to express strong obligation or necessity. It implies that the action is required and there are no alternatives or choices. For example, "I must finish my homework before I go out to play."

2. "Mustn't" is used to express prohibition or something that is not allowed. It indicates that the action is forbidden or against the rules. For example, "You mustn't speak during the exam."

3. "Have to" is used to express general obligation or necessity. It implies that the action is required but there might be some alternatives or choices. For example, "I have to study for my math test tonight."

4. "Don't have to" is used to express the absence of obligation. It means that the action is optional and there is no necessity to do it. For example, "You don't have to bring your umbrella today; it's not going to rain."

5. "Ought to" is used to express a strong recommendation or advice. It suggests that the action is the right thing to do or the best course of action. For example, "You ought to apologize for your mistake."

6. "Need(n't)" is used to express a lack of necessity. It indicates that the action is not necessary and it is fine to not do it. For example, "You needn't worry about the test; it's an easy one."

Now, let's fill in the blanks in the given exercise:

1. "We _______ eat healthier to stay fit." - We ought to eat healthier to stay fit. This is a recommendation or advice to eat healthy.

2. "You _______ eat junk food every day." - You mustn't eat junk food every day. This is a prohibition against eating unhealthy food daily.

3. "They _______ bring their textbooks to class." - They have to bring their textbooks to class. This is a general obligation to bring the textbooks.

4. "She _______ wake up early tomorrow." - She doesn't have to wake up early tomorrow. This indicates that waking up early is optional and not necessary.

5. "He _______ remember to turn off the lights." - He must remember to turn off the lights. This implies a strong obligation to remember and take action.

In summary, the correct forms for the given exercise are: "ought to, mustn't, have to, doesn't have to, must."