Bite off more than you can chew

    自不量力

    这个短语的字面解释是“咬下来嚼不完”，这是什么意思呢？请看对话：

    A: Can you give me the project proposal tomorrow? We are having a formal first meeting with our clients next week.

    B: Sorry, I'm afraid not. I have bitten off more than I can chew by taking on this extra work – I don't think I'll get it finished on time.

    Note: If someone bites off more than he can chew, it means he has agreed to do more than he can manage. This idiom dates back to the 1800s in America, where it was common practice to chew tobacco. People would offer others a bite of their tobacco block, and some would greedily take a bite bigger than they would chew. People began to notice this and forewarned others not to bite off more than they can chew.