题目

Previously we wish some of the things ________ effortless, but we now find them unattainable. A . was B . had been C . were D . has been 答案：B“x＞0”是“1x+1＜1”的（　　）条件．A．充分不必要B．必要不充分C．充要条件D．既不充分也不必要