在工程网络计划执行过程中，当某项工作实际进度出现的偏差超过其总时差，需要采取措施调整

2÷0=0，因为任何数和0相乘都得0．______．

如果a是最小的正整数，b是绝对值最小的数，c与a²互为相反数，那么（a+b）²⁰⁰⁹-c²⁰⁰⁹=______．

阅读理解。

    The question "How long do fish live?" is not as simple as it seems. There are thousands of different kinds

of fishes, and they are quite different from each other in size and life period. What's more, it is not easy to

find out just how long a fish lives in its natural state.

     We can find out how old a fish is by studying its scales, but we can not say how long more it would have

lived if we had not caught it.

     We may keep fishes and record their life period but we can't be sure that this is the length of time they

would have lived had they been left alone.

     We may make marking to show how fast the fishes grow so that we can calculate the age of the largest

on record, but unless this large fish dies of old age we are still not in a position to know its natural life period.

     Unlike human beings, fishes do not stop growing when they have grown up. They continue to grow as

long as they live, although the speed of growth slows down in mature fishes.

1. What can the scales of a fish tell us?[ ]

A. Its age

B. Its life period

C. Its size

D. Its growth speed

2. How can we find out the natural life period of a fish? [ ]

A. We ought to keep a fish with great care.

B. This article refers to no way of settling the problem.

C. We must go on recording while we're keeping a fish.

D. We should make marking of its growth speed and calculate its life period.

3. In the last sentence "mature fishes" refer to _____ fishes. [ ]

A. young

B. sea-water

C. fully-grown

D. fresh water

上市公司向证券交易所申请可转换公司债券上市，应当提交的文件有( )。

A．上市报告书

B．保荐协议和保荐人出具的上市保荐书

C．验资报告

D．申请上市的董事会和股东大会决议

路基设计表汇集了路线（）设计成果。

A.平面

B.纵断面

C.横断面

D.平、纵、横