三极管中，硅管的结构主要是（）。 A.平面型 B.合金型 C.控制型 D.整流型

第一次在全国范围内确立和统一人民调解制度的法规是《（）》，由中央人民政府政务院颁布。

Price continued to rise ______ pay was still low, with the result ______ the government became increasingly unpopular.

A．when; that

B．while; which

C．when; which

D．while; that

动脉血和静脉血的主要差别是（　　）

A．动脉血含氧较多

B．动脉血含养料较丰富

C．动脉血在动脉中，静脉血在静脉中

D．动脉血含废物少

Advertisers tend to think big and perhaps this is why they’re always coming in for criticism. Their critics seem to resent them because they have a flair for self promotion and because they have so much money to throw around. "It’s iniquitous," they say, "that this entirely unproductive industry (if we can call it that) should absorb millions of pounds each year. It only goes to show how much profit the big companies are making. Why don’t they stop advertising and reduce the price of their goods After all, it’s the consumer who pays... "

The poor old consumer! He’d have to pay a great deal more if advertising didn’t create mass markets for products. It is precisely because of the heavy advertising that consumer goods are so cheap. But we get the wrong idea if we think the only purpose of advertising is to sell goods. Another equally important function is to inform. A great deal of the knowledge we have about household goods derives largely from the advertisements we read. Advertisements introduce us to new products or remind us of the existence of the ones we already know about. Supposing you wanted to buy a washing machine, it is more than likely you would obtain details regarding performance, price, etc. , from an advertisement.

Lots of people pretend that they never read advertisements, but this claim may be seriously doubted. It is hardly possible not to read advertisements these days. And what fun they often are, too! Just think what a railway station or a newspaper would be like without advertisements. Would you enjoy gazing at a blank wall or reading railway bylaws while waiting for a train Would you like to read only closely printed columns of news in your daily paper A cheerful, witty advertisement makes such a difference to a drab wall or a newspaper full of the daily ration of calamities.

We must not forget, either, that advertising makes a positive contribution to our pockets. Newspapers, commercial radio and television companies could not subsist without this source of revenue. The fact that we pay so little for our daily paper, or can enjoy so many broadcast programs is due entirely to the money spent by advertisers. Just think what a newspaper would cost if we had to pay its full price !

Another thing we mustn’t forget is the "small ads" which are in virtually every newspaper and magazine. What a tremendously useful service they perform for the community! Just about anything can be accomplished through these columns. For instance, you can find a job, buy or sell a house, announce a birth, marriage or death in what used to be called the "hatch, match and dispatch" column but by far the most fascinating section is the personal or "agony" column. No other item in a newspaper provides such entertaining reading or offers such a deep insight into human nature. It’s the best advertisement for advertising there is!

The passage is ().

A．Narration

B．Description

C．Criticism

D．Argumentation

简述正形投影区别于其它投影的特殊性质。