a fair-weather friend
不能共患难的朋友
A: Doesn't she have any friends?
A: 她没有朋友吗?
B: If she has,they must be fair-weather friends.
B：如果有，也一定是不能共患难的朋友。
A: Such friends are even worse than enemies.
A：这样的朋友甚至比敌人还坏。
B: She'd better keep away from them.
B：她最好离他们远点儿。