it's difficult to make her dream come true，she never gives up

    A Though    B Unless    C Because     D   If

Mary spends a lot of money on clothes _______ her family is not rich.

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

We will have no water to drink _______we don’t protect the earth.

A.until                B.before            C.though            D.if

Scientists say it may be a few years ______it is possible to test the new medicine on patients.

A.because          B.after         C.before            D.since

 You should go over your test paper _____ you hand it in .

    A. before           B. though       C. because      D. as soon as

You have to leave now________you can catch the early bus.

A.so that　　　　 B.as soon as　　　 C.because　　　 D.if

I won’t be able to understand what you say,_______you speak too quickly.

A.if              B.though            C.because

Many students didn’t realize the importance of study_____they left school.

A.when              B.until         C.as            D.after

 Peter likes reading a newspaper     he is having breakfast.

A. until    B. while    C. because  D. though

—Have you got any idea for the summer vacation?

—I don’t mind           . It will be OK if there is sun, sea and beach.

   A. where do we go       B. where we go            C. when we go