We found ________ necessary to protect the environment.
| A．it | B．this | C．that | D．what |
. It is only when you nearly lose someone ____________ you fully realize how much you value him.
| A．do | B．then | C．will | D．that |
--I'm going downtown.
--Come on.
| A．I'll give you a lift | B．You are welcome |
| C．Don't do that | D．Come with me |
--Shall Mary come and play computer games?
--No,__________ she has finished her homework.
| A．when | B．if | C．unless | D．once |
-I'm sorry, I shouldn't have been so rude to you.
--You___________ your temper but that's OK.
| A．have lost | B．had lost | C．did lose | D．were losing |
Whether ways will be found to stop pollution or not is just___________ worries the public.
| A．why | B．which | C．that | D．what |