森林遭到砍伐后，我们可能面临下列哪些问题（ ）
A．水土流失
B．气候改变
C．生物多样性受损
D．以上都可能发生
森林有保持水土的作用，森林的根在地下分布深而广，形成庞大的根系，比地上的枝叶系统还发达．可谓“根深叶茂”，“树大根深”，森林的根系可以牢牢的抓住土壤，防止水土流失．森林能增加空气湿度，调节气候，植物进行蒸腾作用，增加大气的湿度，增加降水，降低温度．如森林上空的空气湿度比无林区高达10-25%左右，比农田高5-10%．据测定，夏天绿地中地温一般要比广场中白地低10-17度．生物必须适应环境才能生存，每种生物都生活在一定的生态系统中，当植物十分丰富的森林生态系统变成单一的农田后，生物种类会迅速减少，破坏了食物链，影响了生态系统的稳定性；当生态系统发生剧烈变化时，一些生物不在适应环境，迁走或死亡，如鸟类和哺乳类大量减少．鸟类减少，各种农林害虫失去天敌的控制，就大量繁殖起来，给农作物和树木造成了严重的危害．因此也会加速种类多样性和基因多样性的丧失．
故选：D．
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| One day I visited an art museum while waiting for my husband to finish a business meeting. I was expecting a quiet 1 of the splendid artwork. A young 2 viewing the paintings ahead of me 3 nonstop between themselves. I watched them a moment and decided the lady was doing all the talking. I admired the mans 4 for putting up with her 5 stream of words. 6 by their noise, I moved on. I met them several times as I moved 7 the various rooms of art. Each time I heard her continuous flow of words, I moved away 8 . I was standing at the counter of the museum gift shop making a 9 when the couple approached the 10 . Before they left, the man 11 into his pocket and pulled out a white object. He 12 it into a long stick and then 13 his way into the coatroom to get his wifes jacket. "Hes a 14 man," the clerk at the counter said. "Most of us would give up if we were blinded at such a young age. During his recovery, he made a promise his life wouldnt change. So, as before, he and his wife come in 15 there is a new art show." "But what does he get out of the art?" I asked. "He cant see." "Cant see! Youre 16 . He sees a lot. More than you and I do," the clerk said. "His wife 17 each painting so he can see it in his head." I learned something about patience, 18 and love that day. I saw the patience of a young wife describing paintings to a person without 19 and the courage of a husband who would not 20 blindness to change his life. And I saw the love shared by two people as I watched this couple walk away, their arms intertwined (交缠). | |||
| ( )1. A. touch ( )2. A. lady ( )3. A. chatted ( )4. A. attempt ( )5. A. vivid ( )6. A. Adopted ( )7. A. through ( )8. A. anxiously ( )9. A. comment ( )10. A. entrance ( )11. A. plugged ( )12. A. made ( )13. A. led ( )14. A. brave ( )15. A. wherever ( )16. A. wrong ( )17. A. describes ( )18. A. kindness ( )19. A. support ( )20. A. get | B. view B. man B. argued B. independence B. constant B. Adapted B. to B. urgently B. decision B. exit B. held B. lengthened B. found B. rough B. whatever B. silly B. draws B. pride B. sight B. hope | C. wander C. couple C. screamed C. wisdom C. casual C. Conducted C. towards C. quickly C. purchase C. front C. reached C. brought C. forced C. smart C. whichever C. equal C. shows C. enthusiasm C. expectation C. allow | D. stare D. clerk D. yelled D. patience D. vague D. Disturbed D. from D. sensibly D. profit D. queue D. bent D. broadened D. tapped D. generous D. whenever D. unique D. decorates D. courage D. confidence D. cause |