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 worker can make chairs ____ wood, and also can make paper ____ wood.
| A．from, of | B．of, from | C．of. of | D．from, from |
The teacher is writing ____ a piece of chalk on the blackboard while the students are writing ____ink in exercise books.
| A．with, in | B．in, with | C．in, in | D．with, with |
—You know. Bob is a little slow ____ understanding, so…
— So I have to be patient ______ him.
| A．in ; with | B．on; with | C．in; to | D．at; for |
We were just about ready to leave _____ it started to snow.
| A．when | B．before |
| C．after | D．since |
_____ the government agrees to give extra money , the theatre will have to close.
| A．Until | B．Unless |
| C．Since | D．While |