为了研究蚂蚁的生活特性，周鹏同学蹲着观察了很长时间，当他突然站起来由于脑部暂时缺血而感到头晕,能用来解释这一现象的物理知识是  （）

管教孩子，避免他们出现行为偏差有三道基本防线：第一道防线是父母，第二道防线是学校，____。在当代社会，由于流动、留守等原因，一些家长监护未成年子女的功能在弱化。____，那就只能期待司法变成“超级父母”了，而这是司法不能承受之重。用刑事处罚和行政处罚去对付“熊孩子”无异饮鸩止渴。最好的方法，一方面是强化家长监护责任，另一方面则是强化学校管教功能，让孩子在学校就能被管好，不让问题“出校园”。实现这一点的前提，就是教师有权威，____。

（节选自《老师能否惩戒“熊孩子”》）

    It's Sunday afternoon. Michael's family have a picnic under (在……下面) a big tree. The woman in a blue T-shirt and white pants is Michael's mother. ⑴She is thirty-two. She is a teacher in No. 2 high School. She is cooking now. The man with a guitar is Michael's father. He is thirty-four years old. ⑵He teaches in the same school as Michael's mother. He is a teacher. Michael's little sister likes singing, but she isn't singing now. ⑶“为什么不和我一起去放风筝呢？”Michael问他的小妹妹。⑷Then she flies a kite with her brother. What a happy family!

辛亥革命后,孙中山进行反对北洋军阀的斗争,其核心目标是（  ）