To bite off more than you can chew 自不量力
成语 bite off more than you can chew 的意思是你不能正确估量自己的能力，对自己估计太高或承担超过自己所能胜任的事情。
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.
David and Sarah planned to completely renovate their house by themselves. In the end, they bit off more than they could chew and had to pay builders to finish it.
Thanks for offering to babysit AND cook dinner for us, but don't bite off more than you can chew.
英语中的另一个同鳄鱼相关的短语是 crocodile tears 相当于汉语中的鳄鱼眼泪，恶人假慈悲。
Louise is crying in the corner because she says the boss upset her – don't pay any attention to her, though – they're just crocodile tears.