问题 名词解释

次生演替

答案

参考答案:

原来有过植被覆盖,后来由于某种原因原有植被消失了,这样的裸地叫次生裸地,有土壤的发育,其中常常还保留着植物的种子或其他繁殖体,环境条件比较好,发生在这种裸地上的群落演替称作次生演替。

生态系统的组成包括生产者、消费者和分解者。所以自然界只要在一定空间内有生物和非生物成分存在,并通过物质和能量流动、信息传递,将它们联系成为一个功能上的整体,这个整体就是一个生态系统。

问答题
单项选择题

Strange things have been happening to England. Still (1) from the dissolution of the empire in the years (2) World War Ⅱ, now the English find they are not even British. As the cherished "United Kingdom" breaks into its (3) parts, Scots are clearly (4) and the Welsh, Welsh. But who exactly are the English What’s left of them, with everything but the (5) half of their island taken away

Going back in time to (6) roots doesn’t help. First came the Celts, then the Romans, then Angles, Saxons, Jutes, Danes. Invasion after invasion, until the Norman Conquest. English national identity only seemed to find its (7) later, on the shifting sands of expansionism, from Elizabethan times onwards. The empire seemed to seal it. But now there’s just England, (8) of a green island in the northern seas, lashed by rain, scarred by two (9) of vicious industrialization fallen (10) dereliction, ruined, as D.H. Lawrence thought, by "the tragedy of ugliness," its abominable architecture.

Of all English institutions, the one to (11) on would surely be the pub. Shelter to Chaucer’s pilgrims, home to Falstaff and Hal, throne of felicity to Dr. Johnson, the pub- that smoky, yeasty den of jollity-is the womb of (12) , if anywhere is. Yet in the midst of this national (13) crisis, the pub, the mainstay of English life, a staff driven (14) into the sump of history, (15) as the Saxons, is suddenly dying and evolving at (16) rates. Closing at something like a rate of more than three a day, pubs have become (17) enough that for the first time since the Domesday Book, more than half the villages in England no longer have one. It’s a rare pub that still (18) , or even limps on, by being what it was (19) to be: a drinking establishment. The old (20) of a pub as a place for a "session," a lengthy, restful, increasingly tipsy evening of swigging, is all but defunct.

11()

A.remember

B.count

C.raise

D.differentiate