题干

下列实验操作与目的描述不相符的是(  )

选项

实验操作

目的

A

光合作用实验中把叶片放入酒精中隔水加热

溶解叶绿素

B

“观察小鱼尾鳍内血液的流动”用浸湿的棉花把小鱼头部的鳃盖和躯干包裹起来,露出口和尾部

防止小鱼乱动,并保证它能正常呼吸

C

观察草履虫时使用棉花纤维

限制草履虫的运动速度

D

在“观察血液分层现象”实验中加入加入抗凝剂

加速血液的凝固

A:A

B:B

C:C

D:D

上一题 下一题 0.0难度 选择题 更新时间:2019-08-22 10:11:54

答案(点此获取答案解析)

D

同类题5

完形填空

Juan loved winter more than any other season. He wasn’t sure   26  , but sometimes he thought about it.   27  it was that cold feeling he had, on a snowy night, looking out at the blowing, falling snow, safe and   28   inside with his family. Or maybe it was   29   those mornings when he could play in the snow with his friends. Christmas, his favorite festival anyway, was always even more   30   when the whole world was white.

  Upstate New York was a(n)   31   place to live in. The summer was warm and green. Autumn was a rainbow(彩虹) of colorful leaves.   32   would arrive in a few months and all would be well in Juan’s world.

  One day, Juan’s grandfather said excitedly, “We are   33   to Florida! No more cold, no more snow or ice, and no more winter!”

  Grandmother Marie was also very   34  . She hugged Juan. “Aren’t you excited, Juan?” she asked, trying not to notice his expression.

  “I don’t want to go there at all. I   35   to live here.” Juan cried.

26 A. when            B. where          C. why

27 A. Perhaps          B. Instead         C. Finally

28A. stupid            B. alone          C. comfortable

29 A. because          B. because of       C. instead of

30 A. special           B. boring          C. silly

31 A. awful            B. great           C. dangerous

32 A. Winter           B. Spring          C. Money

33 A. connecting        B. remaining       C. moving

34 A. sad              B. happy          C. worried

35 A. prefer            B. reject          C. agree