对于直流炉，应设计省煤器入口流量低保护，流量低保护应遵循（）原则。
A、二取一
B、三选中
C、三取二
参考答案：C
健康教育的措施需因人而异、因势利导。这体现了健康教育的（）
A.计划性
B.自主性
C.目的性
D.可塑性
E.差异性
根据首字母提示完成单词 。
1. Dave has worked for 6 hours, so now he is very s .
2. The o day, he bought a present for me.
3. They aren't s enough at that age.
4. He often s___ up reading until midnight.
5. Do you like your school u____?
