问题
选择题
. Tom as well as his classmates __________ a song when the teacher came into the classroom.
A．are singing
B．were singing
C．is singing
D．was singing
答案
答案：D
考查主谓一致。as well as连接两个主语时，谓语动词取决于前者，句意：当老师进入教室的时候，不仅汤姆的同学而且汤姆当时正在唱歌。根据语境表示过去某一时刻进行的动作应用过去进行时态，所以选D。