A.细菌总数≤50cfu/cm3
B.细菌总数≤100cfu/cm3
C.细菌总数≤200cfu/cm3
D.细菌总数≤500cfu/cm3
E.细菌总数≤15cfu/cm3
Whether a large population is good or not has long been a subject of discussion among economists. It has been argued that the supply of good land is limited. To feed a large population, even poorer land must be made use of and the good land is worked too much. Thus, each person produces less and this means a lower average income that could only be dealt with by a smaller population. Other economists have argued that a large population gives more good ideas for plans and the development of ports, roads and railways, which are not likely to be built unless there are more people who want to use them.
One of the difficulties in carrying out a world-wide birth control program lies in the fact that official attitudes to population growth change from country to country. In the developing country where a greatly growing population is pressing hard upon the limits of food and space, the government will try to limit birthrate. In a highly industrialized society a decreasing birthra
A. higher productivity, but a lower average income
B. lower productivity, but a higher average income
C. lower productivity, but a lower average income
D. higher productivity, and a higher average income
Passage Five 5
When you speak, write a letter or make a telephone call, your words carry a message. People communicate with words. But do you think you can communicate without words A smile on your face shows you are happy or friendly. Tears in your eyes tell others that you are sad. When you put up your hand in class, the teacher knows you want to say something or ask a question. You shake your head, and people know you are saying "no". You nod and people know you are saying "yea". Other things can also carry messages. For example, a sign at the bus stop helps you to know which bus to take. A sign on the door tells you where to go in or out. Have you ever noticed that there are a lot of signs around you and that you get messages from them all the time
People can communicate in many other ways. An artist can use his drawings to tell about beautiful mountains, about the blue sea and many other things. Books are written to tell about all t
A. understand the world and other people better
B. teach each other to speak, write, read and draw
C. know what other people are thinking about
D. learn what's happening in the world more quickly
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After 20 years of marriage, a husband may still not understand his wife. How is it that she is never at a (1) for words How can she (2) the names of a couple they met on (3) years ago Now we know (4) to tell him: it’s her brain.
Although there are obviously cultural (5) for the differences in emotions and behavior, (6) breakthrough research reveals that the (7) of many puzzling differences between men and women may (8) in the head. Men’s and women’s brains (9) much in common, but they are definitely not the same (10) size, structure or insight. Broadly speaking, a woman’s brain, like her body, is ten to fifteen per cent smaller than a man’s, (11) the regions dedicated to language may be more densely (12) with brain ceils.
Girls generally speak earlier and read faster. The reason may be (13) females use both sides of the brain when they read. In (14) , males rely only on the left side.
At every age
A. yet
B. hence
C. thus
D. then
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