leave in the lurch 弃…于危难之中;对…坐视不救

【例句】
I helped you a lot when you were in trouble, and now you shouldn't leave me in the lurch.
你有困难的时候我帮了你不少，现在你不应该弃我于危难之时。

They will not leave you in the lurch.
他们不会在你有困难时袖手旁观的。