Answer:
1. The old woman looked up at the sky and said that dark clouds were a sign of rain.
2. She asked me where I would be the next day in case she had to call me.
3. The principal told us to be calm and to listen to him.
Step-by-step explanation:
To report an affirmative sentence, we pay attention to the verb tense. We use the past form of the original tense used in the sentence. We also change the subject, according to whom the speaker is talking to. Expressions of time must be altered to fit the new tense as well (sentence 1)
When reporting a question, we must not only observe the rules above, but also the fact that it will no longer be structured as a question in the new sentence (sentence 2). As for the imperative, we use verbs such as "ask" or "tell", and the reported sentence uses "to" or "not to" (sentence 3).
NOTE:
There is something important to note about the original sentences: not one of them reveals to whom the speakers are talking to. Therefore, there can be different possibilities of reported speech, especially for sentences 2 and 3. Let's use sentence 2 as an example. The original is: “Where will you be tomorrow, in case I have to call you?” she said. But we don't know who "you" is. I chose to make the reported sentence by transforming "you" into "me", as if the woman was talking to me. But she could have been talking to someone else - a man, for instance. In that case, the reported sentence would be: She asked him where he would be the next day in case she had to call him.