bite off more than you can chew
US /baɪt ɔf mɔr ðæn ju kæn tʃu/
UK /baɪt ɔf mɔr ðæn ju kæn tʃu/

1.
自不量力, 贪多嚼不烂
to take on a task that is too big or difficult to handle
:
•
I think I bit off more than I could chew when I agreed to organize the entire conference by myself.
我觉得我同意独自组织整个会议时,是自不量力了。
•
Be careful not to bite off more than you can chew with your new business venture.
开展新业务时,要小心不要自不量力。