20.You have to have a good preparation for the exam__________ you can do well in it.
| A．in order to | B．such that | C．such as | D．so that |
We __________ so tired. We've only been to a party.
| A．mustn't have felt | B．wouldn't have felt |
| C．shouldn't have felt | D．couldn't have felt |
The reason_________ he didn't come was _________ he had to take care of his sick mother.
| A．why ; that | B．why ; which |
| C．which ; why | D．that ; for |
The rescue team made every __________ to find the missing mountain climber.
| A．force | B．energy | C．effort | D．possibility |
"Please __________why you're so late," said his girlfriend.
| A．excuse | B．explain | C．apologize | D．tell |
I'm sorry. I _____________ you__________ to me.
| A．don't know; are speaking |
| B．don't know ;were speaking |
| C．didn't know; were speaking |
| D．didn't know; are speaking |