题干

下列有关显微镜使用的叙述,正确的是(  )

A:对光时,用高倍物镜正对通光孔

B:要使视野变亮,可把低倍物镜换成高倍物镜

C:镜筒下降,当物镜靠近载玻片时两眼注视目镜

D:要使刚观察到的物像更清晰,可调节细准焦螺旋

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答案(点此获取答案解析)

D

同类题4

阅读下列材料,回答问题。

【材料一】1781年(美国独立战争期间)英军在约克敦的投降造成巨大的冲击波,国内舆论纷纷指责政府,指责乔治三世的个人干预造成了北美的巨大失策。……1782年,诺思(首相)顶不住美国革命胜利的冲击波而宣布辞职,乔治三世的个人统治实际上寿终正寝。……一个企图恢复个人权力的国王在议会已取得主导地位的时代想抗拒历史发展的潮流,终于造成国家的伤害、个人的悲剧。

——钱乘旦、许洁明《英国通史》

【材料二】“13个主权国家你争我夺,都在使劲拽邦联的脑袋,很快就会全部崩陷;而惟有一部自由的生气蓬勃的宪法,对防止侵犯权益的行为予以很好的保障和密切注视,才能恢复我们的尊荣的地位和成果,这种地位和成果曾经是我们的正当要求,是我们争取的无限光辉前景。”——华盛顿

“我们的宪法之所以恒久,就在于它简洁。它是一块奠基石,而不是一座完整的大厦。或者用句老话比喻:它是根,而不是完美的藤。”

——美国总统威尔逊

【材料三】长期的分裂局面使得德意志民族无法作为整体来追求国家现代化,因此远远落在英、法等国后面。1870年后,旧的容克地主贵族通过对外战争实现国家统一,并掌握了现代化领导权,在随后短短30年间,德国完成了经济起飞,在工业生产方面甚至超过英、法。不过,现代化领导力量的“错位”给德意志民族带来无穷灾难。为证明其统治的合法性,旧势力一再煽动民族情绪,挑起对外战争,结果德国成为两次世界大战的策源地之一。

一一钱乘旦《各国现代化模式的比较》

请回答

同类题5

完形填空

        I got aboard and sat down in my seat.It was going to be a long flight. Around me were some  1  "Where are you headed?" I asked.

       "Lakes Air Base.We'll be there for special training, and then to the front."

After about an hour, an announcement was made that box lunches were  2  for five dollars. The journey would be several hours, and I decided to buy one.

        As I 3  for my wallet, I heard a soldier ask his fellows if he would buy lunch."No, that seems a lot of money for just a box lunch." I looked around at the other soldiers. 4  were buying lunch.I walked to the back of the plane and  5 the flight attendant a fifty-dollar bill.

        "Take a lunch to all those soldiers." I said.She seized my arms tightly.Her eyes wet with tears, she  6  me, " My son is a soldier in the front...it's almost like you are doing it for him."

       Picking up ten boxes, she headed to the soldiers.

       After eating, on my way to the rest room I was  7  by a man."I saw 8 you did and I want to be part of it." With this, he handed me twenty-five dollars.

       Soon after I returned to my seat, I saw the Flight Captain coming, looking at the seat numbers  9  he walked.When he got to my row he stopped, smiled, held out his10  , and said, "I want to  11  your hand." I stood and took his hand.With a loud voice he said, "I was a soldier.12 , someone bought me a lunch.It was such an act of  13  that I never forgot." I was a little bit  14   when applause rang out from all of the passengers.These soldiers were giving their all for our country.I could only give them a couple of meals.

       Later, when I walked to the front of the plane to stretch my legs, a man  15  another twenty-five dollars in my hand.

When we 16  , I gathered my belongings and started to leave.A man stopped me, put something in my pocket, and walked away 17 a word.Another twenty-five dollars! Seeing the soldiers  18  at the terminal, I walked over to them and handed them seventy-five dollars.As I walked  19  to my car, I prayed for their safe  20  .