几道英语题（要答题理由）

几道英语题（要答题理由）
1.When i came into the room,i noticed my friends （ ）
A.are having a discussion B.discussed C.having a discussion D.to discuss
2.There are about sixteen （ ）people in shanghai in1959
A.millions B.million C.millions D.million of
3.He bought a chineses-english dictionary ( ) this morning.
A.in B.on C./ D.at
4.mrs steward （ ）her house all the morning.she （）to my home
A.was cleaning…didn't B.cleanad…didn't came
C.has cleaned…didn,t D.cleaned…hasn'tcome
5.what ( )last night?
A.did happen to her B.did she happen
C.was happeningto her D.did she happen