2019年mpacc考试英语真题——连词378

{01}She had just finished her homework _____ her mother asked her to practice playing the piano yesterday.
A.when
B.while
C.after
D.since
解析：
本题选A。

{02I had not been reading for half an hour _____ I heard steps outside.
A.while
B.as
C.when
D.since
解析：
本题选C。