Explain the changes in modals when converting from direct to indirect speech.

When converting from direct to indirect speech, there are certain changes that occur in modals. Modals are auxiliary verbs that express possibility, necessity, ability, permission, and other similar concepts. The changes in modals when converting from direct to indirect speech are as follows:

1. "Will" changes to "would": When reporting a statement or question with "will," it changes to "would" in indirect speech. For example, "He said, 'I will come tomorrow'" becomes "He said that he would come tomorrow."

2. "Can" changes to "could": The modal "can" changes to "could" in indirect speech. For instance, "She said, 'I can swim'" becomes "She said that she could swim."

3. "May" changes to "might": The modal "may" changes to "might" in indirect speech. For example, "They said, 'May I leave early?'" becomes "They asked if they might leave early."

4. "Must" changes to "had to" or "must" changes to "had to" or "would have to": The modal "must" changes to "had to" in indirect speech to express obligation or necessity. For instance, "He said, 'I must finish this today'" becomes "He said that he had to finish that day." However, if the speaker is referring to a past event, "must" can also change to "would have to." For example, "She said, 'I must have left my keys at home'" becomes "She said that she would have to have left her keys at home."

5. "Shall" changes to "should" or "would": The modal "shall" changes to "should" or "would" in indirect speech. For example, "He said, 'Shall we go for a walk?'" becomes "He asked if they should go for a walk."

6. "Ought to" changes to "ought to" or "should": The modal "ought to" remains the same in indirect speech, but it can also change to "should." For instance, "She said, 'You ought to apologize'" becomes "She said that he ought to apologize" or "She said that he should apologize."

It is important to note that these changes may vary depending on the context and tense of the reported speech. Additionally, other modals such as "could," "would," "might," "should," and "ought to" generally remain the same in indirect speech.