You were to take your shoes off when you entered the school lab but you didn’t.A. invite

问题补充：

You were to take your shoes off when you entered the school lab, but you didn’t.

A. invited

B. supposed

C. selected

D. approved

答案：

A. invited

(答案→)B. supposed

C. selected

D. approved

解析：be supposed to do sth. 意为“应该做……”。