光学分度头的光学系统视场下部为秒分划板刻线共有600个刻度间隔,由0至20`,角一间隔代表()。
A.1"
B.2"
C.3"
D.4"
参考答案:B
下列物质中, 不能提供人体活动所需能量的是 [ ]
A.葡萄糖
B.油脂
C.酒精
D.食盐
用所给词的适当形式填空。
1. When _____ he _____ (have) science?
2. _____ (he) favorite day is Friday.
3. I like Chinese. It's _____ (interest).
4. My father is _____ (real) busy today.
5. Every day I watch TV for three _____ (hour).