题干

下列各项参与构成人体第二道防线的是(    )

A:皮肤、粘膜

B:体液中的吞噬细胞

C:唾液中的蛋白酶

D:免疫细胞和免疫器官

上一题 下一题 0.0难度 选择题 更新时间:2012-02-21 05:47:48

答案(点此获取答案解析)

B

同类题1

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    Online schools are becoming very popular with many people today. And now, even regular students are going in for online education. As it leaves them with enough time to do other things, such as a part-time job or a hobby, along with studying. However, as with everything, there are two sides about online schooling.

    Let's start with the good side. Online schools cost very little. You don't have to spend money on books, or bus fees. Also, since you can work along with studying at an online schools, you would not need to take an education loan. Another benefit of going to school online is the freedom it provides. You can study wherever you want—in your house, at a cafe or even in a park. Some people who want to study further, now no longer have to take a break in their jobs, thanks to online schools.

    However, those students who often need a push from their teachers to do well have a very high chance of not doing well at online schools. When studying in a class, different topics in a given subject are discussed and different students give their points of view. This is something that online schooling cannot provide.

    Also, there are many employers who prefer students with a regular and traditional degree to those who have an online degree. The employers feel that students who go to full-time colleges have more knowledge compared to those who have online degrees.

    In general, it can be said online schools are good for some, while others should give them up! A person should see the situation he is in and then decide whether or nor to choose an online school.

Are online schools a good idea?

The present situation

Online schools are so popular at present that some regular students also ____ them.

Main point

Online schooling, like everything, has two sides as follows.

Advantages of online schooling

●You spend ____ money at an online school and you can work along with studying.

●You are free at online schools because you can study anytime and anywhere you want.

●If you want to accept further ____, you needn't give up your job thanks to online schools.

Disadvantages of online schooling

●Some students are likely to do badly at online schools for lack of a push from their teachers.

●Students do not have the ____to discuss with their classmates.

●After graduation, students with online degrees are not ____ by many employers.

Conclusion

Whether online schools are good for you is decided by your situation.

同类题5

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    It's time to stop complaining. The economy might be melting down like butter in a hot pot, but for some people — you , maybe? — this could be a very good thing.

    Here's why. At no other time in recent history has it been easier or cheaper to start a new kind of company. Possibly a very profitable company. Let's call these start-ups LILOs, for “a little in, a lot out;” These are Web-based businesses that cost almost nothing to get off the ground yet can turn into great moneymakers.

    How do you get started? All that's required is a great idea for a product that will fill a need in the 21st century. These days you'd do best if your idea either makes people money or saves them money. And launching now will make your company stronger later — you'll learn to survive on fumes until the economy improves.

    That's what John Tayman is doing. He's an author who lives in San Francisco, where I met him; he wrote reviews for a business magazine I edited. Tayman knew little about technology and even less about business. And yet he dreamed of a website that would summarize car reviews from other sources and rank every model of new car. “It'll be like RottenTomatoes.com meets Kelley Blue Book,” he explained to me during lunch one day last June. Tayman said he intended to build the site on the side while continuing to write for a living. He'd work on his new company only at night and on weekends. Oh, yes, and he had only about $10,000. “Good luck with that!” I thought. Ideas are much easier to produce than they are to put into practice.

    Tayman went to work with nothing more than his PowerBook laptop. A very well-organized fellow, he quickly discovered a bunch of free stuff online — instructional manuals and sites that walk you through the process from start to finish. Within months, Tayman had a staff of 20 employees working for him in five different countries. MotorMouths.com went live in January. Tayman figures he has worked about 10 hours a week on it and hasn't spent a cent on marketing or advertising. Growth is modest but steady: nearly 10,000 people visit each week.