----I passed the college entrance examination.
----Congratulations! You________.
| A．could have studied hard | B．must have studied hard |
| C．should have studied hard | D．might have studied hard |
He noticed that the straight part of the dance was different in the afternoon from ________ it had been in the morning.
| A．that | B．where | C．what | D．which |
The shopkeeper did not want to sell for ________ he thought was not enough.
| A．where | B．how |
| C．what | D．which |
Nobody believed his reason for being absent from the class ________ he had to meet his uncle at the airport.
| A．why | B．that |
| C．where | D．because |
With his work completed，the businessman stepped back to his seat，feeling pleased ________ he was a man of action.
| A．which | B．that |
| C．what | D．whether |
The reason ________ he didn’t come is ________ he was ill.
| A．why；that | B．that；why |
| C．why；because | D．why；what |