题目

下列说法：①任何数都有算术平方根；②一个数的算术平方根一定是正数；③a2的算术平方根是a；④(π－4)2的算术平方根是π－4；⑤算术平方根不可能是负数．其中不正确的有( )A. 2个 B. 3个 C. 4个 D. 5个 答案：【答案】C【解析】①因为“负数没有算术平方根”，所以①中说法错误；②因为“0的算术平方根是0，不是正数”，所以②中说法错误；③因为“的算术平方根是”，所以③中说法错误；④因为“的算术平方根是”，所以④中说法错误；⑤因为“算术平方根都是非负数”，所以⑤中说法正确.故选C.此题要求改正所给短文中的错误。对标有题号的每一行做出判断：如无错误，在该行右边横线上画一个勾（√）；如有错误（每行只有一个错误），则按下列情况改正： 该行多一个词：把多余的词用斜线（\）划掉，在该行右边横线上写出该词，并也用斜线划掉。 该行缺一个词：在缺词处加一个漏字符号（^），在该行右边横线上写出该加的词。 该行错一个词：在错的词下划一横线，在该行右边横线上写出改正后的词。 注意：原行没有错的不要改。 Many teachers worry about the effects of television on young people．According to studies, any children spend more time                1．             watching television than they spend in school．Because so                  2．             much viewing, children may not be develop the habit of                      3．             read and the ability to enjoy themselves．No one worries                     4．             much about the radio program young people listen to,                          5．             although radios can be very noise．Teachers also wonder about           6．             the effects of television commercials．On one year the                       7．             average child will see 25,000 television commercials, all                       8．             planned and written by grown-ups to make children to want                 9．             things that they don’t real need．                                                       10．