It is well understood _____ controls the flow of carbon dioxide in and out the atmosphere today.
| A．that | B．when | C．what | D．how |
The reason why I didn’t go to France was __________ a new job.
| A．because I got | B．because of getting | C．I got | D．that I got |
I have no _______ to the plan, so long as it would not cost too much.
| A．refusal | B．comment | C．idea | D．objection |
. Deliver the goods within six months? But that is not a(n) of the contract.
| A．request | B．requirement | C．agreement | D．demand |
51. George Washington was born in 1732 in a rich family in _______ is now the state of Virginia.
| A．which | B．where | C．that | D．what |
The old couple have been married for 40 years and never once _________ with each other.
| A．they had quarreled | B．they have quarreled |
| C．have they quarreled | D．had they quarreled |