---Why you are so worried?
--- I ___for my little son all the afternoon, I don’t know why he hasn’t come back so late.
| A．am waiting | B．have waited | C．have been waiting | D．waited |
—Mary broke up with me!
—You_ _have forgotten about the Valentine's Day．
| A．shouldn't | B．couldn't | C．needn't | D．mustn't |
Have you considered how weak humans area volcano, hurricane or earthquake?
| A．comparing with | B．to compare with |
| C．compared with | D．having been compared with |
Can you explain ________ the sun goes down in the west?
| A．why is it that | B．why it is that | C．how it is that | D．how is it that |
—Someone has tidied the sitting room!
—Jim __ it this morning; he couldn't bear the mess any more．
| A．has done | B．would do | C．had done | D．did |
Peterson used to work in a remote mountain village school, which is only on foot.
| A．reliable | B．accessible | C．available | D．convenient |