问题 实验题

虽然蟾蜍的排卵是有季节性的,但也可以通过向体内注射促性腺激素促进其排卵。为验证促性腺激素有促进蟾蜍排卵的作用,请利用提供的实验材料和用具,设计实验步骤和实验记录表。(注:蟾蜍排卵可通过检查泄殖腔开口处有无卵细胞作为观察指标;不考虑注射激素的剂量;注射激素后只要求观察1次)

材料用具:发育成熟体重相同的雌性蟾蜍6只,注射器,饲养笼,适宜浓度的促性腺激素溶液,0.65%NaCl溶液(蟾蜍用生理盐水)。

(1)实验步骤:_________________________________________。

(2)设计实验记录表格。_________________________________。

答案

(1)①.将6只雌性蟾蜍随机编号1~6,其中编号1~3的蟾蜍作为对照组,4~6的蟾蜍作为实验组,分别放入饲养笼中。

②.检查两组中每只蟾蜍的泄殖腔开口处有无卵细胞,进行记录。

③.实验组每只蟾蜍注射一定量适宜浓度的促性腺激素溶液,对照组每只蟾蜍注射等体积的0.65%NaCl溶液。

④.一定时间后,检查两组中每只蟾蜍的泄殖腔开口处有无卵细胞,进行记录。

(2)

单项选择题
阅读理解

  A train sped up through the countryside at 60 mph as a“traveller”relaxes with his newspaper. But this is no businessman taking it easy—the driver of the passenger express(快车)is doing the reading.

  A Sunday Express reader caught this Virgin employee on film as the train sped through Derbyshire on its way to Plymouth from Newcastle.

  Virgin,which has come under repeated criticism over their rail service, yesterday fired the driver after being shown the photograph. A spokesman said an inquiry(调查)was under way to make sure exactly what he was doing and why he appeared to have taken his eyes off the track ahead.

  The picture comes in the week that the public inquiry into the Southall rail disaster, which claimed seven lives, heard that the driver at the centre of that case had earlier been spotted with his feet on the control button of his cab.

  Larry Harrison,who worked for Great Western Trains,drove through two warning signals before crashing at 60 mph into a waiting train.

  The reader who took this picture was standing on a bridge outside Chesterfield early one summer’s evening. He said,“I only realized what I’d got when I had the pictures developed. I couldn’t believe it.”

  “As far as I could see,there was no one else in the cab with the drive,unless they were hiding, The person with the paper open was certainly sitting in the driver’s normal seat.”

  The photographer works on the railways and does not want to be named,but he added,“I’ve seen many drivers with their feet on the control panel but I’ve never seen them reading papers like this. There is an automatic warning system and driver’s safety device which reminds him when he passes yellow and red signals. But you should never take your eyes off the track and rely only on sounds because you could have unexpected objects on the line or suddenly have speed limits given.”

63.Who is the“traveller”mentioned in the first paragraph?

A.A train driver.       B.A businessman.

C.A passenger.         D.A newspaper reader.

64.The train ______________when the picture was taken.

A.was driving to Plymouth

B.was ready for a picture

C.had seven people on it

D.crashed into another train

65.Who took the picture of the driver of the passenger express?

A.A professional photographer.

B.A newspaper reporter.

C.Another train driver.

D.A member of the railway staff.

66.According to what we have read,we may find this passage most probably______________.

A.at a train station

B.from a news report

C.from a driver’s safety guide

D.from the police inquiry