858.John may phone tonight. I don’t want to go out _____he phones.

　　 A. as long as　 B. in order that　 C. in case　 D. so that　　　　

857. The men will have to wait all day ____the doctor works faster.

　　 A. if　 B. unless　 C. whether　 D. that 　　　　　　　　　　

856. The WTO can’t live up to its name _____it does not include a country that is home to one fifth of mankind.　

　　 A. as long as　　 B. while　 C. if　 D. even though　　　　　

855. Someone called me up in the middle of the night, but they hung up _____I could answer the phone.

A. as　　 B. since　 C. until　 D. before　　　　　　　　　　

854. ----Did you remember to give Mary the money you owned her?

----Yes, I gave it to her_____I saw her.

A. while　 B. the moment　 C. suddenly　 D. once　　　　　　　

853. I’d like to stop working ______I’ve got too much work still to do.

A. because　 B. though　　 C. if　　 D. and

852. If this TV doesn’t work, bring it back ______we’ll give you your money back.

A. but　　 B. because　　 C. since　 D. and　

851．----I am going to the post office.

　 　----_______you’re there, can you get me some stamps?

　 　A. As　　 B. While　 C. Because　 D. If　　　　　　　

850. ----Have you taken a message for him?

　 ---I will tell him ______I see him.

　 　　A. at the moment　　 B. in an instant　 C. the moment　 D. the time　　

849. A man escaped from the prison last night. It was a long time ____the guards discovered what had happened.

　 　A. before　　 B. until　 C. since　 D. when