题目

中东地区一些国家的人们夜晚常把床铺安排在屋顶上，这是因为：（ ） A.可以欣赏美丽的星空        B.当地的气候炎热，极少下雨 C.当地昼夜温差大          D.当地气候温和湿润 答案：B　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　 阅读下列短文，从所给的四个选项中，选出最佳答案 　Plants seem to know which way is up and which way is down; they seem to know right from left. If a cutting from a Lombardy polar is kept alive, new shoots will grow from the end that grew uppermost in the tree. 　There is no visible difference between the top and the bottom of the living stick, even under a microscope. Even so, the stick will not send out shoots from the end it considers as bottom even if this end happens to be on top! 　Scientists studying this subject further break their cuttings lengthwise(从上至下). To their surprise, they made shoots grow on the right-hand side of the broken surface than on the left. They cut the sticks again and found that the shots again grew on the right side. (1) In this passage“uppermost”means“______”. [　　] A．at the top　　　B．in most parts C．mostly　　　　D．in the upper part (2) In this passage, “a Lombary polar” is probably a ______. [　　] A．cutting　　　B．cutting surface C．tree　　　　D．stick (3) “up” and “down” on a cutting are decided by the ______. [　　] A．position in which the cutting is planted B．kind of plant from which the cutting was taken C．“up” and “down” of the plant it was taken from D．size of the cutting (4) Socialists examining the ends of a fresh cutting find ______. [　　] A．very little difference between them B．one end slightly darker than the other C．no difference between them D．a difference that only the microscope shows (5) If a cutting is placed upside down in the laboratory, ______. [　　] A．leaves will grow from the part on top B．leaves will grow from the original(原来的)"up" end C．leave will grow at either end D．leave will not grow any more