题目

实数4的算术平方根是（ ）A. B.± C.2 D.±2 答案：【答案】C【解析】利用算术平方根的概念：一般地，如果一个正数x的平方等于a，即x2＝a，那么这个正数x叫做a的算术平方根，记为．进而得出答案．解：实数4的算术平方根是2，故选：C．选词填空。look, dressed, take, gifts, was【1】Did they ________ pictures yesterday?【2】We ________ up and made a funny play.【3】How ________ your holiday?【4】Come and ________ at my pictures.【5】These ________ are for your children.