A $\stackrel{X}{\to }$ B $\stackrel{Y}{\to }$ C $\stackrel{Y}{\to }$ D $\stackrel{Z}{\to }$ E

当X是强酸时，A,B,C,D,E均含有同一种元素，当X是强碱时，A、B、C、D、E均含有另外同一种元素．请回答：

    Good evening, everyone! Today, I'm very glad1a speech2name is "My Dream". We know everyone has his or her own dream. Some people want to be basketball players because they are good3sports. Some would like to become4 because they like to stay with children. Do you know5I'm going to be when I grow up? I like cooking,6 I want to become a good cook. I think I must have great7 cooking food. I'd like to ask everyone to taste my food. I also like seeing their smiling faces after8the delicious food. However, it's not so9to be a good cook. I decided to learn 10things about cooking from now on. I will work hard for my dream. I'm sure I will succeed (成功) one day.

把肯定句改成否定句。

①他这样做虽然过分了点，但还是有道理的。

②我们建成了希望小学。