Question

Sally took a photo of her friends while they _________ computer games

1. A.
   play
2. B.
   are playing
3. C.
   have played
4. D.
   were playing

Answer 1

D
根据句意“塞丽为朋友照相”和下文句意“当他们玩电脑游戏时”可知，两个动作同时发生，while后常接进行时。
【考点】动词的时态。