已知函数y=f(x)在区间(a,b)内可导，且x₀∈（a，b）则 的值为（  ）

下列根据实验现象所得出的结论中，正确的是（　　）

请在图中画出反射光线，并标出反射角的大小。

2011年春节过后，部分地区出现了用工难，浙江宁波有些企业，采用了以下留人招数。招数一，“给迟回的员工买好机票”；招数二，“涨工资涨福利留人”；招数三，“奖励员工免费出国旅游”；招数四，“报销生育费用帮助解决员工孩子上学难问题”；招数五，“平时做足工作”。像浙江这些精明的企业老板，把职工当成企业最宝贵的“财富”而“以情留人”，年后就不会再有“用工难”。材料体现了劳动者享有（  ）
①取得劳动报酬的权利         ②休息、休假的权利
③获得劳动安全卫生保护的权利 ④享受社会福利的权利

阅读理解B
Paul：Good morning, Alan．
Alan：Good morning, Paul．Look at that boy．I never(从未)saw him before．
Paul：The boy in the blue jacket?
Alan：No. The boy is in red．He is playing baseball．
Paul：Oh, he is a new student in my class．His name is Mike Smith．
Alan：He plays well!
Paul：Yes, he is on the baseball team(队). His father is good at it, too．
Alan：Is his father a baseball player(运动员)?
Paul：No, he is a doctor．
Alan：What about his mother?
Paul：His mother is an English teacher in our school. She is nice．
Alan：When did they come to Shanghai'?
Paul：Last month. They will live here for a year and then go to Beijing．
Alan：You know a lot about Mike．
Paul：Yes. We' re good friends．
根据材料内容选择最佳答案。