支持矿质元素主动吸收的载体学说有哪些实验证据？并解释之。

“When can I get a cell phone?” The answer is when your parents think you need one, though many kids seem to be getting them around age 12 or 13. Some younger kids may have them because their parents see it as a matter of safety and convenience. For example, a kid can call mom and dad when sports practice is over. And a cell phone can give kids almost instant access(快捷通道) to their parents if something goes wrong or they need help. It can give parents quick access to their kids so they can check on them and make sure they’re OK.

If you do get a cell phone, make some rules with your parents, such as how many minutes you’re allowed to spend on the phone, when you can use your phone, when the phone must be turned off, and what you will do if someone calls you too often, and so on.

You’ll also have to learn to take care of the phone in your life. Keep it charged(充电) and store it in the safe place so it doesn’t get lost. And whatever you do, don’t use it in the bathroom. I know someone who dropped her phone in the toilet! 

小题1:Parents buy cell phones for their kids because ___________.

A．they think it is necessary

B．they think their kids are old enough

C．they have asked the author for advice

D．they want to follow their kids wherever they are.小题2:The author of the passage ___________.

A．wants to describe how children use cell phones

B．knows nothing about when children can have a cell phone

C．may have done a survey on kids using cell phones

D．has been a teacher for many years小题3:Which of the following is true?

A．It is too young for kids of 12 or 13 to get a cell phone.

B．A cell phone is useful for kids and their parents.

C．The author is against the idea of kids to have cell phones.

D．Most kids are considering having cell phones.小题4:Who is the passage most probably written by?

A．Parents who have bought phones for their kids.

B．Someone who does cell phone business.

C．A teacher who cares most about school safety.

D．Someone who works for children’s education.小题5: Which might not be a rule for kids with a cell phone?

A．Keep it on all the time.

B．Make a call if something goes wrong.

C．Don’t use it in the bathroom.

D．Take care not to lose it.

任何哲学思想都不是凭空产生的，马克思主义哲学的产生也不是偶然的，它有着深厚的阶级基础、自然科学基础和理论来源。

(1)马克思主义产生的阶级基础是什么?(3分)

(2)简述马克思主义哲学产生的理论来源。(6分)

易燃和可燃液体的燃烧是液体本身在燃烧。（）

类风湿性关节炎活动期的标志是（）

A．畸形

B．压痛

C．梭状指

D．自发痛

E．晨僵