29. Sometimes we have to face embarrassing moments ________ we can only keep silent.
A
who
B
which
C
when
D
why
24. I wonder whether his hearing is okay ______ he has turned the television up very loud.
27. You’d better make the plants shorter, ______ they will interrupt the views from the house.
21. The ceiling’s low, _____ you need to be careful not to hit your head.
句意：有时候我们不得不面对只能保持沉默的令人尴尬的时候。此处为when引导的定语从句修饰先行词moments。故选C。
定语从句
判断结构
抓不住要点
难度适中