tear it直译过来就是：“撕破它，撕掉它”，这个短语的正确意思是：“打破计划，使希望破灭，使计划泡汤”。因此，当美国人说"That tears it!"时，他/她要表达的意思就是:"I'm fed up with it."、"I've had enough."。
Jane: Work overtime! That tears it! The boss doesn't give me a raise!
Shirley: Anyway, take it easy!
①He promises many times to give me a raise but never realizes it.
②The pay slip reads that my salary doesn't get raised at all.
③I'm transferred to Vietnam to do foreign trade for a year.
④The manager has appointed that beautiful girl to be his assistant instead of me.