Only  when  one loses  freedom  _______its value  .

A.  does one know     B. one does  know   C. does  know one         D. know one does

Well  let  you  use  the  room  ______you  keep  it   clean  and  tidy  .

 A. even   though    B. on  condition  that   C.  if      D. however 

 Is    this   the  research   center   _____you   visited the lab  last   year  ?

A.  which    B.  the one   C.that   D. where

Don’t  believe   him  .He   is  just   _____  an   excuse  .

 A. making    out   B. making   up  of   C. making   up   D.  making from         

-Would you mind if I take the seat?

         -         .

A．Yes, sit down, please                                               B．Surely, never mind

C．No, not at all                                                    D．No, you can’t take it

The bell rang and came in Mr.Brown,    a book in his hand. Then the class began.

A．for                                  B．when                    C．with                      D．while

In the past 5 years a great deal of money _____ improving the environment of the school.

    A. is spent      B. has been spent   C. was spent     D. had been spent

China has been working very hard to stop the endangered animals ______ .

    A. dying out      B. dying away      C. dying down    D. dying hard

 I ______their   method   of   making   the  machine  .

     A. adopted    B.  voted   C.  elected   D.   commanded   

The blues has been _____part of African-American culture since then, and it is still ______ important part of American culture.

A. a; a       B. / ; an               C. the ; a           D. / ; a