参考翻译习题答案如下：

1. The service in this shop has been bad before, but this is the last straw.

2. The last of these rows seems to have been the last straw.

3. 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.

4. You've been late for work too often. This is the last straw. You're fired.

5. The last straw was when I heard someone humming behind me.