[单项选择](Neither) rain (nor) sleet nor snow (keep) the mailman from his (appointed) rounds.
A. Neither
B. nor
C. keep
D. appointed

[单项选择](Neither) rain (nor) sleet nor (keep) the mailman from his (appointed) rounds.
A. Neither
B. nor
C. keep
D. appointed

[单项选择] Neither rain nor snow (keeps) the postman from delivering our letters (which) we (so much) look forward to (receive.)
A. keeps
B. which
C. so much
D. receuve

[单项选择]The sharp rise of the snow geese population is mainly caused by______.
A. lack of natural enemies
B. great care of wildlife preservationists
C. favorable conditions in their winter habitat
D. changes in their migration patterns

[单项选择]The heavy snow could not keep us ______ going out to work.
A. from
B. on
C. upon
D. up

[单项选择]In spite of the heavy snow and hard rain, the buses still ran on ______.
A. list
B. plan
C. arrangement
D. schedule

[单项选择]Acid rain
A. immediately kills trees and affects aquatic life in lakes and rivers.
B. deposits various metals iron, mercury, aluminum into the soil.
C. kills forests by weakening them and reduces fish populations.
D. releases sulfur dioxide, nitrogen oxide and into the atmosphere.

[单项选择]—There has been no rain for months. Will it rain soon —______. The crops are in great need of water.

[单项选择]What makes rain fall

[单项选择]

Computer systems are usually divided into four main types according to their size. They are supercomputers, mainframe computers, minicomputers and microcomputers.
Microcomputers , also called personal computers, are small computers fit on a desk top and are usually only used by one person. They are the least expensive types, and are widely used in businesses for all kinds of tasks, such as word-processing, small data-base management, and spreadsheets. They are also used as home computers, for family budgeting and similar jobs, as well as for games. Compared with a mainframe computer, minicom puters are smaller systems, and fewer operators can use them. They are usually found in medium-size business or in divisions within a large organization, for example in Government departments. Mainframe computers are large and powerful computers. Many people can use at the same time. They are also expensive systems. They are used for very large processing tasks, and perform ma
A. home computers
B. minicomputers
C. special computers
D. supercomputers