Inland waters may be grouped into two general classes: standing waters and flowing waters.

Inland waters may be grouped into two general classes: standing waters and flowing waters. As is often the case, the boundary between these two classes is not sharp and clear. A pond is an example of standing water. But most ponds are fed by springs or brooks and most have an outlet. Thus some current of changing water flows through them. On the other hand, a river is an example of flowing water. In some places, however, a river may have such a slow current that it is very difficult to detect.
Standing inland waters differ in size, in age, and in many abiotic environmental characteristics. They range in size from roadside puddles to the Caspian Sea. Puddles may last for only a few days or weeks; ponds, for a few hundred to a thousand years. In general, lakes are older, though the waters of some tropical “lakes” disappear completely during each dry season. Standing waters vary from very shallow to very deep, from clear to muddy, from fresh to salty.
In flowing waters we roughly distinguish between brooks, creeks, and rivers. The size and age of flowing waters are unimportant. Speed of flow, clearness, oxygen content, and other chemical characteristics are used by scientists in studying flowing-water ecosystems.
【小题1】According to the passage, which of the following characteristics of flowing waters is unimportant? A．Clarity.B．Size.C．Speed of flow.D．Oxygen content.【小题2】The word “abiotic” in paragraph 2 can best be replaced by .A．nonlivingB．livingC．coastalD．inland【小题3】Which of the following statements is true?A．Usually the water in a river flows into a pond.B．Scientists only study flowing-water ecosystems.C．Usually ponds last much longer than puddles.D．The Caspian Sea is considered as an example of flowing water.【小题4】From this passage we may know that the distinction between standing waters and flowing waters .A．depends on how people name the watersB．is clearC．depends on the seasonsD．is hard to make【小题5】This passage mainly tells us that .A．there are two major classes of inland watersB．lakes and rivers are flowing watersC．age and size of flowing waters are importantD．ponds and brooks are standing watersB

(答案→)B 解析：文章介绍了内陆有两大水域，静止的水域和流动的水域，具体介绍了它们不同，但是确切的区分二者还是很难的。【小题1】细节题：从文章第三段的句子：The size and age of flowing waters are unimportant.可知流动的水的大小是不重要的，选B【小题2】猜词题：从文章第二段的句子：Standing inland waters differ in size, in age, and in many abiotic environmental characteristics.因为是静止的内陆水域，可知“abiotic” 是“无生命的”，选A【小题3】细节题：从文章第二段的句子：Puddles may last for only a few days or weeks; ponds, for a few hundred to a thousand years. 可知水池比水坑持续时间长，选C【小题4】细节题：从第一段的句子：Inland waters may be grouped into two general classes: standing waters and flowing waters. As is often the case, the boundary between these two classes is not sharp and clear. 可知静止的水和流动的水很难界定，选D【小题5】主旨题：从全篇文章和第一段的句子：可知这篇文章讲的是内陆有两大水域，选A

这个答案应该是对的