题干

在观察蚕豆叶下表皮实验时,李明同学用显微镜先后在视野中看到了不同的物像效果,如图2所示.请回答下列问题:

(1)在显微镜的结构中,最重要的部件是[____ ]____ 和[____ ]____

(2)李明在实验中,观察到的效果由甲变成乙,他应将装片向____ 移动.

(3)观察效果由乙变成丙,他应该转动____ ,由低倍物镜换成高倍物镜.但换成高倍物镜后,李明发现,视野变暗了,这时他应转动遮光器选择____ 光圈,同时转动反光镜选择____面镜.

(4)观察效果由丙到丁,他应调节显微镜的[____ ]____

上一题 下一题 0.0难度 选择题 更新时间:2018-06-26 06:37:17

答案(点此获取答案解析)

A,目镜,C,物镜,左方,转换器,大,凹,D,细准焦螺旋

同类题3

根据短文内容,从短文后的选项中选出能填入空白处的最佳选项。选项中有两项为多余选项。

Breaking theHabit of Comparing Yourself with Others

   If  you took the strengths of others, and compared them with your weaknesses, youwould feel rather upset. This is what most of us do at one time or another—andsome of us do pretty often. It's a sure­fire recipe for a drop inself­confidence and for unhappiness. ____Here are some tips that might behelpful to you:

   Awareness.Most often we make these social comparisons without realizing we're doing them.It's a natural act, I suppose, and as a result it's something that is donewithout consciousness.____Bringthe thought to your consciousness by being on the lookout for them. If youfocus on these thoughts for a few days, it gets much easier with practice, andsoon it won't be hard to notice.

   Stop yourself. Once you realize you're doing these comparisons, giveyourself a pause.____Justacknowledge the thought, and gently change focus.

   Count your blessings. A better focus is on what you do have, on what you arealready blessed with.____ Think about how lucky you are to have what youhave, to have the people in your life who care about you, to be alive.

    Focus on your strengths. Instead of looking at your weaknesses, ask yourself whatyour strengths are. Celebrate them ! Be proud of them. Don't brag, but feelgood about them and use them to your best advantage.

____ Sometimes we try to criticize others just tomake ourselves look or feel better. Attacking someone else for your benefit isdestructive. It forms an enemy when it could form a friend. In the end, thathurts you as well. Instead, try to support others in their success—that willlead to more success on your part.

a.Don't knock others down.

b.Don't blame yourself or feel bad.

c.So the solution is to become conscious.

d.Helping others means helping yourself.

e.Count what you have, not what you don't.

f.It is important to try to find out your strengths.

g.So how do you break this cycle of comparing yourself withothers?