【题目】We thought there were 35 students in the lecture hall, __________, in fact, there were 40.
A.while
B.whether
C.what
D.which

【答案】A
【解析】句意是：我原以为餐厅有35位学生，可是事实上有40人。这题考查连词while的用法：这里while表示 “然而”，选A。