下列现象不可能出现的是（   ）

    It's Saturday morning. My parents and I are on a tour bus. There are about twenty people on the bus. Some are from America, and some are from England and Australia. They are all our friends. We are going to the Great Wall. On the bus, there are two Chinese. One is a woman, the other is a man. The woman is good at English. She is talking with us about the Great Wall. The other people are listening to her. They like the Great Wall. They want to see it very much.

设函数D(x)＝，则下列结论错误的是   （   ）

已知二次函数y=ax²+bx+c（a≠0）的图象如图所示，则下列四个结论：①abc＞0；②3a+b＞0；③$\frac{c}{a}$＞-3； ④2c＞3b，其中结论正确的个数为（）