课桌椅的卫生学要求有（）。 A.适合儿童身材，为良好坐姿提供外_爱下问搜题

搜题请搜索小程序“爱下问搜题”

问题单项选择题

课桌椅的卫生学要求有（）。

A.适合儿童身材，为良好坐姿提供外部条件

B.不妨碍正常生长发育

C.少产生疲劳

D.保护视力

E.以上都对

答案

参考答案：E

填空题

用方框中所给单词的适当形式填空。

success coat happy introduce encourage

1. The boys and girls are playing _______ in the park.
2. There is no doubt that we will be _______ in passing the exams.
3. Although I failed four times, my parents _______ me to have a fifth try.
4. My old _______ are so short that I want to buy some new ones.
5. Listen! The tour guide is _______   the history of Three Lanes and Seven Alleys.

填空题

SQL SELECT语句中的【】用于实现关系的选择操作。