Complete the sentences using the most suitable form of 'be' (simple or continuous).

{"q": "Complete the sentences using the most suitable form of 'be'.", "a": "1. I can't understand why he's being so selfish. He isn't usually like that.
2. Jack is being very nice to me at the moment. I wonder why.
3. You'll like Jill when you meet her. She is very nice.
4. Normally you are very sensible, so why are you being so silly about this matter?
5. Why isn't Sarah at work today? Is she ill?"}