下列说法不正确的是
A．青铜中含有的主要合金元素是锡和铅
B．装运浓硫酸的铝罐车，在卸货后不能用水冲洗铝罐的内部
C．半导体工业所说的“从沙滩到用户”是指将二氧化硅制成晶体硅
D．氮的固定只有在高温、高压、催化剂的条件下才能实现
答案：D
题目分析：A、青铜是Cu、Sn、Pb的合金，所以含有的主要合金元素是锡和铅，正确；B、若用水冲洗，则残留的浓硫酸变稀硫酸，稀硫酸与铝反应，腐蚀铝罐车内部，所以不能用水冲洗铝罐的内部，正确；C、沙滩中的沙子的主要成分是二氧化硅，而硅常用作半导体材料，正确；D、氮的固定分为自然固氮和人工固氮，自然固氮不需要高温、高压、催化剂的条件，错误，答案选D。
After his parents’ meeting , Wang Jiaming , 14 , from Beijing knows that he will face invisible（看不见的）“enemies”—“other excellent students”. “Look at such and such a student . You and he are taught by the same teachers . Why couldn’ t you be as as him ?”his mother would say . Many students hear words from their parents . After the parents’ meeting , their parents begin to them with other students , especially those who are praised by teachers . “I want to encourage my child to them ,”explained Li Shulan , a mother of a 14-year-old boy from Xi’an , Shanxi . However , many children , like Wang , don’ t like it . “I feel very and sometimes even‘hate’those students ,”Wang said . Parents have good intentions（意图）, but in fact they could children’ s self-esteem（自尊）, said Lin Ying , a psychological（心理的）teacher at Xiamen Hubin Middle School in Fujian . If children feel hurt , they should let parents know it . “You can choose a relaxing occasion , for example , over the dinner , and tell your parents your feelings ,”Lin said .“Also , some articles online explain it could be bad for children . You may want to show such articles to your parents .” It’ s not all bad , though . Liu Jiayang , 13 , from Taizhou , Zhejiang said students could take the chance to learn to be open-minded . “I find the students that my mom talks about really have strong that I don’ t have . I take them as examples and try to with them ,”she said . “During the process（过程）, always keep in mind that you’ re unique（特别的）. Never heart ,”Lin added .
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