The flu is believed ______ by viruses that like toreproduce in the cells inside the human nose and throat

. —-You just think of yourself! You kept me waiting for at least three hours．—-I am sorry that you _____ think so.

We learned in geography class that the earth __________around the sun.

Would you mind carrying the box for me — _______

Outside，the wind to pick up，and the rain started coming down even harder.