超弦理论认为:粒子是由什么构成的()
A、几何点
B、节点
C、弦
D、弧
参考答案:C
用适当的介词填空。
1. It's a fine day today. Let's go ______a drive.
2. The children went camping _______ the rain.
3. What did they do______their first day off?
4. We watched a movie ______ dolphins.
5. ______ the end of the day, the children were very happy.
关于妇女一生各阶段生理特点,下列哪项正确:
A.幼童期儿童体格及内外生殖器同时发育
B.第二性征的出现标志青春期开始
C.月经初潮标志卵巢功能成熟为性成熟的开始
D.更年期一般历时3年
E.卵巢激素减少至不能引起子宫内膜脱落出血,历时1年以上,最后一次月经过后称为绝经