He _______ have completed his work；otherwise, he wouldn’t be enjoying himself by the seaside.

Is that your best friend Kitty?— No, it _________ be her. She flew to Singapore yesterday.

You _______ have told her the bad news last night, because she wouldn’t handle it peacefully.

—Did you visit the museum last week? —No, we _____, but we spent too much time shopping.

— ______ you sing the English song?— Yes, I can. But only a little.