[单项选择]Essentially all polar ice forms from precipitation that falls as snow. Extremely cold air cannot hold much moisture and consequently cannot produce much snowfall, in recent years, air masses in both polar regions have been, without exception, extremely cold.
The information above most strongly supports which of the following conclusions
A. If polar ice is currently growing and expanding at all, it is doing so only slowly.
B. If air temperatures in the polar regions were considerably warmer, much polar ice would melt off.
C. In the last few years, snowfall in the polar regions has been virtually continuous.
D. The thicker the polar ice is, the colder the air masses that are in contact with it.
E. (E) For snow to turn into ice in the polar regions, the air has to be extremely cold.

[单项选择]Why don’t all ice crystals in clouds immediately fall to Earth（　）.
A. They are balanced by the pressure of rain droplets.
B. The effect of gravity at high altitude is random.
C. They are kept in the sky by air current.
D. They are moving about with fixed direction.

[填空题]In 1925, all forms of art

[单项选择]Direct advertising includes all forms of sales appeals, mailed, delivered, or exhibited directly to the prospective buyer of an advertised product or service, without use of any indirect medium, such as newspapers or television. Direct advertising logically may be divided into three broad classifications, namely, direct-mail advertising, mail order advertising, and unmailed direct advertising.
All forms of sales appeals that are sent through the mails are considered direct-mall advertising. The chief functions of direct-mail advertising are to familiarize prospective buyers with a product, its name, its maker, and its merits and with the products local distributors. The direct-mall appeal is designed also to support the sales activities of retailers by encouraging the continued patronage of both old and new customers.
When no personal selling is involved, other methods are needed to persuade people to send in orders by mail. In addition to newspapers, magazines, radio, and te
A. includes all forms of sales appeals to the prospective buyer
B. is produced mainly for newspaper or television
C. is an activity by which real products are shown to buyers
D. uses post as a chief means to contact prospective buyers

[单项选择]

Direct adverting includes all forms of sales appeals, mailed, delivered, or exhibited directly to the prospective buyer of an advertised product or service, without use of any indirect medium, such as newspapers or television. Direct advertising logically may be divided into three broad classifications, namely, direct-mail advertising, mail order advertising, and unmailed direct advertising.
All forms of sales appeals that are sent through the mails are considered direct-mail advertising. The chief functions of direct-mail advertising are to familiarize prospective buyers with a product, its name, its maker, and its merits and with the product’s local distributors. The direct-mail appeal is designed also to support the sales activities of retailers by encouraging the continued patronage of both old and new customers.
When no personal selling is involved, other methods are needed to persuade people to send in orders by mall. In addition to newspapers, magazin
A. direct advertising is the best way to promote a product
B. companies are trying to find the best way to sell their products
C. advertising is becoming enriched by the research in this area
D. old ways of advertising is giving ways to new ways of doing it