问题补充:
my teacher didn tell me directly, I still felt that I didn live up to her expectation.
A. When
B. Since
C. As
D. While
答案:
A. When
B. Since
C. As
(答案→)D. While
解析:D考察连词。句义:虽然老师没有直接告诉我,但是我仍然感觉到辜负了她的期望。While在本句中作为连词,意为:虽然;when既然,当…时;since因为,由于;as因为,随着;根据语境可知D正确。