Question

几道英语题目求助！！

1.Is there a magic cut off period ____ children become responsible for their own actions?
A that B on which C which D when
2.Mr.Li has gone abroad already ,____ he can't attend our opening ceremony tomorrow.
A above all B all in all C in other words D in the end
3.Clever as he is,_____ he doesn't work hard enough to pass the test.
A but B however C so D yet
请高手们给出解题原因！谢谢！

Answer 1

1.D 这是一道定语从句，先行词为period时期,所以应该是填when
2.B above all 毕竟 all in all 所以 in other words 其他方面 in the end 最后，根据语意选B
3.A 他很聪明，但他不够勤奋去通过考试，表转折关系，所以选A.