下列不是必需脂肪酸的主要功能的是（） A.构成磷脂的重要成分 B.合成前列腺素的前体

2008年1月1日，某公司以融资租赁方式租入固定资产，租赁期为8年，租金总额为8800万元。假定在租赁期开始日最低租赁付款额的现值为7000万元，租赁资产的公允价值为8000万元，租赁内含利率为10%，另外以银行存款支付初始直接费用50万元。则该项融资租入固定资产的入账价值为( )万元。

A．7000

B．7050

C．8050

D．8800

依据《大气污染防治法》，( )依照国务院规定的条件和程序，核定企业事业单位的主要大气污染物排放总量，核发主要大气污染物排放许可证。

A．国务院

B．国家环保总局

C．大气污染物总量控制区内有关地方人民政府

D．大气污染物总量控制区内有关地方环境保护行政主管部门

实验室制取时，要收集干燥纯净的氯气，应使氯气依次通过

A．水、浓H₂SO₄

B．饱和Na₂CO₃溶液、浓H₂SO₄

C．饱和NaCl溶液、浓H₂SO₄

D．饱和NaHCO₃溶液、浓H₂SO₄

阅读理解。

    Why don't birds get lost on their long migratory (迁居的) flights? Scientists have

puzzled over this question for many years. Now they're beginning to fill in the blanks.

    Not long ago, experiments showed that birds rely on the sun to guide them during

daylight hours. But what about birds that fly mainly by night? Tests with artificial (人

造的) stars have proved conclusively that certain night-flying birds are able to follow

the stars in their long-distance flights.

    One such bird-a warbler (鸣禽)-had spent its lifetime in a cage and had never flown

under a natural sky. Yet it showed an inborn ability to use the stars for guidance. The

bird's cage was placed under an artificial star-filled sky at migration time. The bird

tried to fly in the same direction as that taken by his outdoor cousins. Any change in

the direction of the make-be-live stars caused a change in the direction of his flight.

    Scientists think that warblers, when flying in daylight, use the sun for guidance.

But the stars are apparently their principal means of navigation (导航). What do they do

when the stars are hidden by clouds? Apparently, they find their way by such landmarks as

mountain ranges, coast lines, and river courses. But when it's too dark to see these, the

warblers circle helplessly, unable to get their direction.

1. The reasons why birds don't get lost on migratory flights _____. [ ]

A. have been known to scientists for many years

B. have only recently been discovered

C. are known by everyone

D. will probably remain a mystery

2. Warblers migrate _____. [ ]

A. from North America to South America

B. only once during their lifetime

C. using what is apparently an inborn navigational ability

D. when they are freed from their cages

3. When the stars are hidden by clouds, warblers find their way by _____. [ ]

A. an artificial star

B. their inborn ability

C. some landmarks

D. wind

4. This article is a good example of the way scientists _____. [ ]

A. jump to conclusions

B. discover workable (可行的) answers to general questions by studying particular cases

C. find a law and then investigate (调查)

D. are disappointed by the habits of animals

(单选或多选组成)

甲公司中止交货并要求乙公司提供担保，行使的是《合同法》规定的( )。

A．同时履行抗辩权

B．后履行抗辩权

C．不安抗辩权

D．撤销权