题目

下列说法不正确的是（ ） A . 质量数是将原子核内所有的质子和中子的相对质量取整数值之和 B . 表示一种X元素的一种原子，中子数为A-Z C . 中，A为该原子的相对原子质量的近似值 D . 原子都是质子和中子、电子组成，原子不带电 答案：D根据课文内容填空，个别空格可能不止一一个单词。U3: It's not 1. to be the same, My best friend is quite 2.from me...We both like sports, but he plays tennis better... Larry often helps to3.the best in me. I always get better grades than he 4. so maybe I should help him more...I know she cares about me because she's always 5.to listenU4: It's always interesting to watch other people show their 6.... All these shows try to look for the best singers, the most exciting magicians, the funniest singers 7.. All kinds of people join these shows. But who can play the piano the best or sing 8.? That's9.to decide. When people watch the show, they usually 10.deciding the winner.