题干

下列关于高倍镜使用的描述,错误的是( )

A:先在低倍镜下看清楚,再转至高倍镜

B:先用粗准焦螺旋调节,再用细准焦螺旋调节

C:把视野调亮,图像才清晰

D:高倍镜看到的细胞图像变大,观察到的细胞数目变少

上一题 下一题 0.0难度 选择题 更新时间:2018-06-26 09:33:34

答案(点此获取答案解析)

B

同类题3

阅读下面短文,从短文后各题所给的四个选项(A, B, C和D)中,选出可以填入空白处的最佳选项,并在答题卡上将该项涂黑。

     “Daily Star, sir” called Jason, carrying some newspapers under his arm. The little boy had been running up and down the street, but there were still twenty 1 left. His voice was almost gone and his heart was 2. The shops would soon close, and all the people would go home. He would have to go home too, carrying the papers 3 money. He had hoped to sell more papers tonight to make more money to buy a4for his mother and some seeds for his bird. That was why he had bought the papers with all his money. He 5 as he thought of his failure to sell all his papers.

     “You don't know the 6of selling papers. You must shout, “Hot news! Bomb bursting!” another newsboy Chad told Jason. “7 it's not in the paper at all,” replied Jason. “Just run away quickly 8they have time to see, and you'll 9out and get your money,” Chad said.

    It was a new 10to Jason. He thought of his bird with no 11 and the cake he wanted to buy for his mother, but was 12 that he would not tell a lie. Though he was 13 a poor newsboy, he had been 14 some good things.

The next afternoon Jason went to the office for his papers 15 Several boys were crowding around Chad, who declared with a 16 smile that he sold six dozen the day before. He added that Jason 17 money because he would not tell a lie. The boy 18 at Jason. “You wouldn't tell a lie yesterday, my boy?” A gentleman at the office came up and patted Jason's shoulder 19.”You're just the boy I am looking for.” A week later, Jason started his new20. He lost sale of twenty papers because he would not tell a lie, but got a well-paid job because he told the truth.

同类题4

       阅读《幸福为何总在遥远的山那边》,回答小题。
      小时候曾听过一首外国民谣,不知何故,那头几句就一直印在脑子里。这两句是,在那遥远的山那边,人说幸福就住在那里……
后来年事渐长,每想起这两句词,就产生疑问,幸福为何一定要住在山的那一边?如果住在这边,住得近一点不可以吗?我一直有这疑问,但又不敢问人。怕问出来,人家会笑我傻。而且我隐隐约约地感觉,即便是拿出来问人,大概也得不到什么答案。
稍稍长大以后,我开始偶尔看到,并蓄意去注意看起来好像很幸福的人。我想,幸福的人必是幸福住在他们家,他们才会幸福。幸福肯住在他们家,他们当然与旁人很不一样。
      看到一些幸福的人,果然是很不一样的。譬如,常看到一对夫妇从一栋白色的花园宅邸走出来,衣着华丽,大声嬉闹,不时发出阵阵哄笑。我想,他们都是幸福的。
       当时,我们家很穷,父亲不在,母亲天天以泪洗面。我们几个兄弟姐妹都觉得我们是很不幸福的。
      凡是幸福的人,都是很陌生的人;凡是我比较熟悉的人,好像都不怎么幸福。我的二姑妈嫁到了一家很富有的人家,听母亲说,姑妈应当很幸福的。但二姑妈每次到我们家就向母亲倾诉婆婆待她不好,丈夫欺负她。有一次,我还看到她悄悄擦眼泪。自此,在我心目中,她那身华丽的衣服不再代表幸福。大姊也出嫁了,嫁的是很体面的人家。她每次回来,面带微笑。邻居们都对母亲说,你女儿嫁得好幸福啊。母亲与大姊都笑笑默认。但我好几次看到她们两人单独相对时黯然无言,神色悲戚。我不敢问,但我感觉得出,大姊并不幸福,而且非常不快乐。
       于是我开始有一点了解:幸福一定是在很遥远的地方,一定是住在山的那一边。因为遥远的人是美丽的,陌生的人是很遥远的。陌生的人走来走去,穿着华丽的衣服,微笑,结伴游湖,谈笑风生。你只看见他们的幸福,你并不知他们回家后不微笑、不谈笑风生的时间,是否擦过眼泪,是否神色悲戚。
母亲生了一场病后,脸色苍白,身体很弱。她要去菜市场,我有点不放心。我说要陪她去。母亲说:“你在家用功读书。”但我一再坚持,母亲便欣然同意。
      一路上母亲拉着我的手,我一手替母亲拿着篮子。我们买的不多,因为我们只有买一点青菜的钱。回途上,遇到一位从前的邻居太太。邻居太太拉着母亲的手大惊小怪地问: “哟,你的儿子长了好多了,上中学了?”“今年刚刚考上初中,省立初中。”母亲微笑着回答。“啊!好聪明的儿子,还会替你拿篮子!你真幸福!”
      母亲没有回答,但母亲笑了笑,笑得很开心。我从未看过母亲笑得如此开心。我觉得母亲可能在那一刹那,是真正幸福的。我突然觉得,我和母亲都在一个很遥远很遥远的地方。