IT IS NOT RAINING NOW, BUT WHEN I CAME TO SCHOOL THIS MORNING, IT...

37. - 3500 CAU TRAC NGHIEM ON TAP AV THCS
3500 CAU TRAC NGHIEM ON TAP AV THCS

37. It is not raining now, but when I came to school this morning, it

...very hard.

a. is raining

b. was raining

c. has rained

d. has been raining

 b