下列有关生物实验及操作的叙述，正确的是（） A．当低倍镜下

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问题选择题

下列有关生物实验及操作的叙述，正确的是（）

A．当低倍镜下观察细胞不清晰时，应换上高倍镜观察

B．实验中出现误差是不可避免的，但应尽量减少误差，不能出现错误

C．测量小石块的体积时，测三次，其中最大一次为最后的体积数值

D．调查校园的生物种类，应选择一条生物种类少、环境变化小的路线

答案

答案：B

题目分析：A、当低倍镜下观察细胞不清晰时，应调节细准焦螺旋，使图象清晰，故A错误；

B、实验中出现误差是不可避免的，但应尽量减少误差，不能出现错误，故B正确；

C、测量小石块的体积时，测三次，为减少误差应当取三次的平均值，故C错误；

D、调查校园的生物种类，应选择一条生物种类多、环境有较大变化的路线，故D错误。

故选B

多项选择题

二氧化碳气腹引起高碳酸血症和酸碱平衡紊乱与哪些因素有关

A．二氧化碳经腹膜吸收入血

B．气腹压的作用

C．二氧化碳蓄积作用

D．手术时间长

E．以上都不是

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完形填空

It was a sunny day. A city man was driving along a country road with a new wagon（马车）and a beautiful pair of horses. He didn’t pay a lot of      to where he was going. Pretty soon he    that he was lost, but he     to drive, expecting to re-find his way or to    someone who could tell him how to get back to the      .
It was a long     road. For many hours he kept on driving. When it was almost      ，he saw in a     a tall farmer ploughing（犁地） the land. He stopped his       team of horses near the fence and called out，“Hello，farmer.”
“Hello，yourself，”the farmer replied，      ploughing.
“Where does the horse       ？”he asked without knowing his language mistakes.
“I haven’t seen it go anywhere. It        stays right where it is，”said the farmer，    stopping his work.
“How far is it to the next town？” said the city man，speaking a little       .
“Don’t know. I never     it,” replied the farmer. By this time the city man was getting      .“What do you know？You’re the biggest fool I      saw.”
     stopping, the farmer turned and looked for a long time      at the city man. Then he said，“Maybe I don’t know much.     I am a fool. But at least I’m not lost！”

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