__________ some medals came to live in the sea is not known.

A. Which          B. Since          C. Although     D. How

Mr. Li has ordered ___ for the school lab.

A. three equipments             B. three pieces of equipments 

C.three pieces of equipment       D. three pieces equipment

There ___ no water in the well.

        A. has        B. are      C. is         D. have

We should make a careful study of his____.

A.     useful teaching experiences      B.useful teaching experience

C.usefully teaching experiences      D. usefully teaching experience

 --- Hello, is Mary in?

--- I'm sorry she ____ come to the phone because she is having a bath.

A. won't B. mustn't C. can't D. wouldn't

How I wish that you could attend the party, even though you _____busy.

  A.had been    B. would be    C. were     D. are

It doesn’t make a(an)_______to me whether you go or stay.

A. difference    B. point    C. deal     D. effort

— How are the team playing ?

— They are playing well, but one of them _____ hurt.

A. got      B. gets       C. are       D. were

___ most of the earth’s surface is covered by water, fresh water is very rare and precious.

A. As B. Once C. If D. Although

They kept trying _____ they must have known it was hopeless.?

　　A. if         B. because?    C. when       D. where??