─You look so tired, Celia!  ─Yes. I          volleyball the whole afternoon.

There _______ less air pollution in the country .

---Is this your dictionary? ---Yes. I ________ it for two weeks. (Which is NOT right?)

A: Alice, please tell Eric to call me when he _________ back. B: No problem. 

Mark Twain ______ school and began to work at the age of twelve.