receive+accept:
Receive是指客观上的接受.、接收这种行为和动作，并不涉及主观意愿。
I received his letter. 一般疑问句 Did you receive his letter? Yes, I did . No, I didn't.
Accept是指主观上自愿主动去接受、接纳，也可以说是思考过某人或某物在某方面足够好、满足自己的期望而接受。
She accepted his proposal of marriage.
一般疑问句 : Did She accept his proposal of marriage? Yes, She did. No, she didn't .
如： I have a good time here, but I must leave now. 我在这儿玩得很开心，但现在得走了。而have to则强调客观上的需要，如：My grandma can’t look after herself, so I have to take care of her. 我
have+to/+must的一般疑问句及肯定否定回答
must 只有现在时一种形式(在宾语从句中可以表示过去),而 have to则有多种时态形式。
must表示主观上认为有义务或有责任必须做某事，而have to则强调客观上的需要，
如 I must leave now. Must I leave now? Yes, I must, No, I must not.
如：I have to take care of her. Do you have to take care of her? Yes, I do , No, I don't.