问题补充:
You can’t complain about being left out you don’t make any effort to share your joys and sorrows with others.
A. once
B. unless
C. when
D. though
答案:
A. once
B. unless
(答案→)C. when
D. though
解析:句意,当你不能和别人分享你的快乐和痛苦时,你就不能抱怨被丢弃。Once一旦 unless除非 when 当……时 though尽管,根据题意,故选C。