As you          the tasks, cross them off your list so you may feel less pressure. 

---where have you been?---I___in the heavy traffic, or I would have been here earlier.

.To improve your health, you can _________ 25— 30 minutes three or four times a week to do simple things such as walking ,cycling or running .

The thieves ran away when the burglar alarm(防盗警报器)       .

________， he came to know how great his mother was.