急！请问assume、adopt、undertake有什么区别？

assume
1. suppose something: to accept that something is true without checking or confirming it
Don't assume that all has been revealed.

2. take responsibility for something: to start being responsible for something
She assumed all of her brother's debts when he died.

3. adopt something: to adopt or take on a quality
The task facing them assumed Herculean proportions.

4. undertake role: to undertake a role or function
assume a new role as sales director

5. pretend something: to put on a pretense of something, usually in order to hide true feelings
He assumed an air of indifference.
adopt
1. legally raise another's child: to raise a child of other biological parents as if it were your own, in accordance with formal legal procedures
2. choose and decide to use something: to take up something such as a plan, idea, cause, or practice and use or follow it
decided t