填空题 The students ____ (are having/were having) a singing class now.

填空题 What ____ (is/was) your mother ____ (did/doing) now?

填空题 They ____ (didn't go/don't go) to the hospital with us yesterday.

填空题 Susan ____ (is doing/was doing) her homework at nine last night.

填空题 What ____ (were/are) you ____ (doing/did) at 3 o'clock yesterday afternoon?

填空题 When I ____ (come/came) in just now, the little girl ____ (was lying/is lying) in bed.

填空题 When the teacher ____ (comes/came) into the classroom, every student was playing mobile phones.

填空题 The boy often ____ (plays/playing) cyber games on the Internet.