完成句子。

l. That ______ (不可能) he Mary. She's in hospital.

2. — Could I borrow your dictionary? 

    — Yes, of course you ______ (可以).

3. — When can I come for the photos? I need them tomorrow afternoon.

    — They ______ (应该) be ready by 12:00.

4. — Shall I tell John about it?

    — No, you ______ (不必). I've told him already.

5. — May I pick a flower in the garden?

    — No, you ______ (一定不能).