The service in this shop has been bad before, but this is the last straw.
这家商店的服务一向不好，但这一次实在是叫人受不了。
The last of these rows seems to have been the last straw.
这场口角看来是彻底破裂的导火线。
Bill had a bad day in school yesterday. He lost his knife on the way home, then he fell down, and when he broke a shoe lace, that was the last straw and he began to cry.
