效用函数和无差异曲线:have sth to do \have sth do\have sth done的区别

have sth to do \have sth do\have sth done的区别 关于have sth. to do的两个句子 have to do sth 被动语态怎么改？ WHICH IS BETTER?:have chances to do sth. OR have chances doing sth. have sb do sth. 是什么意思 请问continu to do sth 和continu to have been doing agree to do sth agree to do sth有吗? 用pefer to do sth rather to do sth造句 be rich( )to do sth help sb. do sth还是help sb to do sth?