题干

当一个婴儿体细胞中第13对染色体多了一条时,就会导致先天性唇裂.在下列生殖细胞中,哪两种生殖细胞的结合会产生先天性唇裂的男性患儿(A表示常染色体)?(  )

①23A﹢X    ②22A﹢X    ③21A﹢Y     ④22A﹢Y

A:①和③

B:②和③

C:①和④

D:②和④

上一题 下一题 0.0难度 选择题 更新时间:2018-01-09 11:24:25

答案(点此获取答案解析)

C

同类题3

    Greg Woodburn, a university student, spends a lot of time cleaning sports shoes. Some of them once belonged to him; some belonged to his friends. But soon the shoes will have new owners, poor children in the USA and 20 other countries, thanks to Greg's Share Our Soles(鞋底) (S.O.S) charity. 
    Greg was a high school running star in a small town in California. He had to stop running for months because his knee was injured. "I started thinking about all the things I got from running, the health, the friendships and the confidence."he says. And I realized there are children who don't even have shoes.
    Greg collected his own sports shoes and then called his friends and the town. His aim was to have 100 pairs by Christmas 2006. When the number climbed to more than 500 pairs. Greg know that he could collect sports shoes all year round.
    Now he has set up collection boxes in his town. So far, S.O.S has collected and donated more than 3,000 pairs of shoes. And Greg has cleaned almost all of them. “People think of it as duty work,”he says, "but I like doing it, because I feel happy when I'm doing it. It's not work I want to pass on to someone else.”
    In just three years, Greg has started three branches(分部) of S.O.S and there are more and more sports shoes.
    For many poor children who have received the shoes mean opportunity. Two young boys in southern California used to go to school on alternate days(隔日) because they both shared a pair of shoes. They were too big for one boy and too small for the other. Thanks to S.O.S, each brother received his own pair of shoes. The boys now go to school every day. When they graduate, they say they will help others, just as Greg helped them.

同类题4

阅读下面的文字,完成小题。

    《逍遥游》是《庄子》内7篇之首,又是整部《庄子》的开卷第一篇。不管《内篇》是否庄子手订,把《逍遥游》放在首篇,客观上也的确显示了它在整个《庄子》中的突出地位。这足以证明编书者是一位对庄子思想理解极深又有高明见解的人。

    庄子是中国文化史上一种独特的思想学说——逍遥哲学——的开创者。“逍遥”一词在《诗经》中就已经出现,但作为哲学概念和对人生心理状态的抽象哲学概括来使用,却始于《庄子》。它的内涵虽然继承了《诗经》中的基本义项,但总体而言又不同于《诗经》中的“逍遥”,而是更丰富了。从《逍遥游》的内容来看,“逍遥”在这里是指一种超凡脱俗,不为身外之物所累的一种心理状态和精神境界,近乎我们今天所说的“绝对自由”。追求“逍遥”是庄子人生哲学的主要内容,也是整个庄子思想的核心。庄子思想的庞大体系,就是围绕着这个核心构建起来的,其他一切思想观念和理论元素无不与这一核心存在着紧密联系。正是在这个基本点上,显示了庄子思想区别于其他任何一种思想体系的主要特质。因此我们可以说,庄子的整个思想体系就是一整套关于追求“逍遥”的“逍遥哲学”。若从“逍遥哲学”这个角度来观察庄子思想的各个部分,我们就会发现,庄子的自然哲学是它的理论基础,庄子的相对主义是它的认识论根源和走向逍遥境界的思想方法,庄子的社会思想是它产生及形成的心理土壤,庄子的文学思想和创作风格是它的具体表现和外化形式。

    庄子认为,宇宙中包括人类在内的万事万物都是不逍遥的,因为它的存在和生活方式都是“有所待”的,即有条件的、受限制的,因而都是不自由的,即使那些自以为逍遥,表面上看去也貌似逍遥的人与物,也是如此。比如,在《逍遥游》中描写的貌似逍遥的大鹏,是很不自由的,因为体型太大,飞翔时不仅需凭飓风之力来托负,而且还必须有大的空间才能展翅。正是由于这个原因,它才受到小鸟斥鴳的嘲笑。斥鴳认为自己的生活方式比大鹏优越,是最自由的。其实这正反映了它由于生活环境的狭小所带来的局限,因为它无能力到广阔天地中去遨游,形成了目光短浅的习性。这讲的是万物在空间上的局限。

    在时间上也是如此。朝菌不可能了解一天之外发生的事情,寒蝉不可能知道一年四季的变化,而生命长的灵龟和大椿也不能知道其生前死后的事。这讲的就是万物在时间上的局限。至于人类,看上去似乎比动、植物自由得多,实际上他们所受的限制也更多,除了名、利、富、贵之外,还有伦理道德、感情欲望等多种牵累,而且对死亡的恐惧和担忧的精神负担,远远超过其他生物。从受限制这个角度来审视人生,人是世界上所有事物之中最不自由的。所以庄子认为只有“无己”的“至人”、“无功”的“神人”、“无名”的“圣人”才是进入绝对自由境界的人,这就是庄子的理想人格,而“逍遥游”也就成了庄子理想的人生境界。

(节选于《智通庄子——游心于物之初》)