My classmate( )( )( )a lot of good deeds for others.
has been done
B. did
C. was doing
D. had done

单项选择题( )( )( ) in this light, the matter is not as serious as people generally suppose.To seeB. SeenC. SeeingD. Being seen

单项选择题The number of teachers in this school（）unknown.

A.are
B.is being
C.is
D.are being

单项选择题A number of paintings in the castle are believed( )( )( )in a fire.being destroyedB. having been destroyedC. to be destroyedD. to have been destroyed

单项选择题Middle school boys( )( )( )not to smoke.

单项选择题The class ( )( )( ) over, we had a ( )( )( )discussion.

单项选择题We specialize ( ) the exportation of Chinese light industrial products.

单项选择题The method is ( ) cheaper and safer.

单项选择题Which of the following choices is not the compulsory component of business letters?

单项选择题I would like to take advantage ( ) the discount to place an order with you.

单项选择题Which of the following is focused on writing?