It be the vocabulary that caused you the problem in the exercise because you know a lot of words.
| A．may |
| B．couldn’t |
| C．should |
| D．needn’t |
Some researchers believe that there is no doubt ______ a cure for AIDS will be found.
| A．which | B．that | C．what | D．whether |
The place _______ the bridge is supposed to be built should be________the cross-river traffic is the heaviest.
| A．which; where | B．at which; which | C．at which; where | D．which; in which |
The shopkeeper did not want to sell for ________ he thought was not enough.
| A．where | B．how | C．what | D．Which |
Danby left word with my secretary ________ he would call again in the afternoon.
| A．who | B．that | C．as | D．which |
Do you have any ideas ________ is actually going on in the classroom?
| A．that | B．what | C．as | D．Which |