Question

to bite off more than you can chew - I think she's bitten off more than she can chew. She comes home tired and miserable every night.  - Are you sure you're not biting off more than you can chew? You know nothing about computers and yet you've applied to be IT manager!  - I am beginning to suspect that I bit off more than I could chew by starting this goddamn blog!  - Having bitten off more than he can chew in Iraq, President Bush wants to start on Iran?

Accepted Answer

to attempt something that is too difficult If you bite off a large piece of meat, it will fill your mouth and you will find it difficult to chew and swallow it.

Idiom	to bite off more than you can chew
Definition	to attempt something that is too difficult
Examples	- I think she's bitten off more than she can chew. She comes home tired and miserable every night. - Are you sure you're not biting off more than you can chew? You know nothing about computers and yet you've applied to be IT manager! - I am beginning to suspect that I bit off more than I could chew by starting this goddamn blog! - Having bitten off more than he can chew in Iraq, President Bush wants to start on Iran?
Note	If you bite off a large piece of meat, it will fill your mouth and you will find it difficult to chew and swallow it.

Chew I Bite Difficult Bitten Attempt She's Home