Basketball is so popular a game in the world that ______ people play it for fun and exercise.
A. million of B. millions of C. millions D. two millions of
Don't be afraid of asking for help ______it is needed.
A. when B. after C. 
although D. unless
I want to know______do to improve my English.
A. what I can B. what can I C. how I can D. how can I
It's important______the piano well.
A. of him to play B. for him to play
C. of him playing D. for him playing
一_______ the sports meeting might be put off(推迟).
一Yes, it all depends on the weather.
A. I told B. I’ve told C. I’ve been told D. I’m told
一Have you mended your bike，Bob?
一Yes，I______it twenty minutes ago.
A. have mended B. mend C. had mended D. mended
