I am so tired，for I ________ English for 2 hours.
| A．is studying | B．have been studying |
| C．was studying | D．had been studying |
30．When you finish your work, don’t forget to put the tools back where they ________．
| A．are | B．will be | C．were | D．had been |
29．The police tried to get some clues from the suspect, but he remained________
| A．silent | B．quiet | C．calm | D．secret |
27．In hot weather, an old tyre can break again easily _____it’s mended．
| A．when | B．where | C．which | D．that |
26．PE will be part of the high school graduation examinations．______,you will have to be strong and healthy to graduate．
| A．After all | B．As a matter of fact | C．In other words | D．What’s more |
25．If you sleep short of 7 hours, you are three times _______ to catch a cold．
| A．possible | B．certainly | C．probable | D．likely |