爸爸打算给亮亮的小书房铺上方砖，用边长2分米的方砖需要90块，

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问题解答题

爸爸打算给亮亮的小书房铺上方砖，用边长2分米的方砖需要90块，如果改用边长3分米的方砖，需要方砖多少块？（用比例解）

答案

设需要方砖X块．

3×3×X=2×2×90；

9X=360；

X=40．

答：需要方砖40块．

阅读理解

阅读理解，判断对"√"错" × "。

Amy is my best friend. She's a nice girl. She's ten. She's tall and quiet. She has long hair and a small

mouth. She has big eyes and a small nose. She likes music, computer games and painting. She likes books,

too. She has fifty story books. She is a good student. I like her very much.

( ) 1. Amy is my sister.

( ) 2. Amy is not quiet.

( ) 3. Amy has 15 story books.

( ) 4. Amy likes painting and music.

( ) 5. Amy has long hair and a small mouth.

判断题

分段分批加药，会降低药剂的选择性，并使药剂消耗量增加。