题目

不等式2x2-5x-3≥0成立的一个必要不充分条件是（ ）A.x≥0      B.x＜0或x＞2   C.x＜-   D.x≤-或x≥3 答案：.B    根据对话内容判断正误，对的用T，错的用F。Teacher: Mike, what do you think about the life in 2050.Mike: Oh, I think there will be many robots. And they will help people do everything.Teacher: Can you give me an example?Mike: For example, the robots can help people with the housework.Teacher: What else?Mike: I also believe that people will work and study at home.Teacher: Uh……, what do you feel about it?Mike: I think it will provide more convenient for people, but it may make people be lazy.Teacher: I agree with you, thanks for your answer.( ) 1. Mike thinks there will be many robots in 2050.( ) 2. The teacher thinks the robots will help people do everything.( ) 3. Mike gives an example about the robots.( ) 4. Mike thinks that the robots are prefect.( ) 5. The teacher also thinks the robots will make people become lazy .