题干

观察显微镜时,双眼的状态是(  )

A:只睁开左眼

B:双眼睁开,用左眼看目镜

C:只睁开右眼

D:双眼睁开,用右眼看目镜

上一题 下一题 0.0难度 选择题 更新时间:2020-01-03 07:12:40

答案(点此获取答案解析)

B

同类题1

阅读下文,回答问题

神奇的魔术师

冬苗

       ①女儿小海伦的生日就要到了,约当茨却高兴不起来。

       ②妻子小心翼翼地与他商量:“女儿想多邀些小朋友,开个生日‘派对’好不好?”“随你安排吧!”约当茨大手一挥,不耐烦地说。“小海伦一直把你当作心目中的英雄,大伙也想听你讲海上的惊险故事呢!”妻子柔声细语地说,“呃,对了,还有一位魔术师要来表演,他自己找上门,不好意思拒绝。”“魔术师?哈哈,混饭吃的江湖骗子!”灼当茨放声欠笑,笑声很空洞。妻子惊恐地望着他,不知丈夫发生了什么事。

       ③小海伦生日那天,来了不少小客人。屋子里,就像涌进一群花喜鹊,热闹极了。

       ④男主人却不问不闻,衔着雪茄,独自去河边散步了。约当茨这次远航归来,郁郁寡欢,心事重重。自约当茨从河边回来时,魔术表演己近尾声。看来的确很精彩,院子里不时爆出哄笑声、鼓掌声。妻子嗔怒地瞟了他一眼,连忙让出座位,“哎,你到哪儿去了?到处找不到你。这魔术太奇妙了!你不看,真可惜啦!”“骗小孩子而已!”约当茨鄙夷不屑地哼了一声。

       ⑤“唷,这位先生刚刚钓鱼回来吧?收获不小啊!”魔术师年岁已老,发须斑白,但精神矍铄。他向约当茨高声喊话,吸引了大家的注意。“呵,说我吗?”顷刻间,约当茨成了全场的焦点。“我帮你把鱼儿放进盆里!”魔术师端来一瓷盆,走到约当茨身旁,果然从他藤椅的前后左右,一把把抓出活蹦欢跳的金鱼来,扔进水里还能游动。“好,压轴戏由我们大明星登场啦!”魔术师用口哨吹奏进行曲,一条漂亮的斑点狗蹦到台前。眼看魔术师扔出礼帽,原来只是虚晃一枪,礼帽急藏身后。斑点狗果真上了当,东嗅嗅,西扒扒,不见礼帽的影踪,最后,竟从灌木丛中,艰难地拖出一只大皮靴来。它一步一趔趄,气喘吁吁地把大皮靴拖到主人的脚边。更加意外的是,魔术师竟从大皮靴里抱出一只红眼睛的小白兔,送给小海伦,作为生日礼物。全场的孩子都兴奋得尖叫起来,欢乐的气氛达到了顶点。

       ⑥约当茨也忍不住鼓起了掌,笑出了眼泪,吩咐妻子送上丰厚的酬金。魔术师却不肯收受,只和约当茨干了一杯葡萄酒。他说,年轻时他是名消防队员,火灾中,为抢救医院里的病人,被砸下的横粱压断双腿。他拉起裤管露出金属假肢,寒光凛凛,使约当茨全身一震。

       ⑦一切都明白了。他是从医院里知道了约当茨的情况,才特意赶来。与这位神奇的魔术师相比,约当茨作最坏的打算,也仅仅将据去一条腿,难道就到了世界末日?

       ⑧夕阳下,约当茨目送魔术师的汽车渐渐远去,轻轻用口哨吹起了《手手进行曲》. 天空明净,微风拂面,远处的青山更青了!

同类题4

阅读下面材料, 从每题所给的A, B, C, D四个选项中选出最佳选项。

C

    Life is full of surprises and you never know how things will turn out. Sir John Gurdon. Is a good example of this. As a boy, he was told he was hopeless at science and finished bottom of his class. Now, aged 79, the very same Gurdon shared the 2012 Nobel Prize in Medicine with Japanese stem cell (干细胞) researcher Shinya Yamanaka.

    Like so many scientists, Gurdon shows us where the power of curiosity and perseverance (坚持) can lead.

    At the age of 15 in 1948, Gurdon ranked last out of the 250 boys at his high school in biology and every other science subject. Gurdon's high school science teacher even said that his dream of becoming a scientist was quite "ridiculous".

    In spite of his teacher's criticisms, Gurdon followed his curiosity and kept working hard. He went to the laboratory earlier and left later than anyone else. He experienced thousands of failures.

    "I believe that we will, in the end, understand everything about how cells actually work." Gurdon said.

    In 1962, Gurdon took a sell from an adult frog and moved its genetic (基因的) information i nto an egg cell. The egg cell then grown into a clone of the adult frog. This technique later helped to create Dolly the sheep in 1996, the first cloned mammal in the world.

    In 2006, Gurdon's work was developed by Yamanaka to show that a sample (样本) of a person's skin can be used to create stem cells. Using the technique, doctors can repair a patient's heart after a heart attack.

    "Luck prefers the prepared mind." Gurdon told the Nobel Prize organization. "Ninety percent of the time things don't work, but when they do, you have to catch the chance."