问题
选择题
Sally took a photo of her friends while they_____computer games.
A．play
B．are playing
C．have played
D．were playing
答案
答案：D
题目分析：句意：Sally照了一张她朋友们玩电脑游戏的照片。while“当...时候”，后面跟进行时或延续性动词。本题主句一搬过去时，从句发生在过去正在进行的动作，因此要用过去进行时。故选D。