What happened __________ you, Mary ? You looked so sad.—I couldn’t find my MP3. It’s a present from my mother.[ ]

The old man _______ a pair of glasses is Li Lei’s grandfather. [ ]

How many birds can you see in the trees?—I can see birds in them.

Simon ishis English book, but he can’t _______ it.

I don’t know the new word. — It doesn’t matter, you can ______ in the dictionary.