— You’d better keep quiet in class.
— Sometimes I . Yesterday, I was as quiet as a mouse during my English class.
A. would
B. do
C. did
D. was
网友回答
A. would
(答案→)B. do
C. did
D. was
解析：此题考查谓语替代词do 的用法。此处do指代keep quiet in class，根据前面的sometimes 可知，指的是经常性的行为，用do而不用did。