题干

下列有关细胞的叙述,正确的是

A:病毒是一类具有细胞结构的生物

B:蓝藻细胞具有细胞核且DNA分子呈环状

C:人体所有细胞的细胞周期持续时间相同

D:细胞膜和细胞器的膜都具有流动性

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答案(点此获取答案解析)

D

同类题3

阅读下面的文章,完成文后题目。

                                                                                            看轻自己
      年长的人总是忘不了给那些踌躇满志的年轻人忠告:在人生的路上,要多把自己看轻些。这忠告,包含着几缕沧桑,但更多的是对生活的一种超越。
  诗人鲁藜说:“老是把自己当珍珠,就时常有怕被埋没的痛苦。还是把自己当做泥土吧!让众人把你踩成路。”
看轻自己是一种人生哲学,看轻自己才能“飞”起来。
  在现实生活中,有些人习惯以自我为中心,以自己为主角,总把自己看得太重,而偏偏又把别人看得太轻。为此,总以为自己很了不起,以为自己博学多才,满腹经纶,一心想干大事,创大业;总以为别人这也不行,那也不行,惟独自己最行;总以为自己成绩最大,功劳最多,记功评奖、加薪晋级不在话下。否则,就不高兴,牢骚满腹,怪话连篇。自认怀才不遇的人,往往看不到别人的优秀;愤世嫉俗的人,往往看不到世界的精彩。把自己看得太重的人,心理容易失去平衡,个性往往脆弱,实际表现为独断、骄横、傲慢,盛气凌人,与社会格格不入……这种人,外界不仅不会接受,反而会遭到嘲笑和孤立,使你变得停滞不前。
      看轻自己是一种智慧。为人处事,盲目自信就会先把自己置于一种不利位置。越是看轻自己,越易被人看重。你真诚的谦卑,将使大家折服,他们乐意在你周围歌唱;你力所不及的柔弱,会为大家所同情,他们愿意倾其所有,助你强盛。看轻你自己,才能做到轻装上阵,没有任何负担地踏上漫漫征程,你的人生路途才能获得更多帮助和教益。
  看轻自己是一种风度,一种境界,一种修养。其实,把自己看轻,这是光明磊落的心灵折射,是无私无畏的自然反映,是正直坦诚的自由流露。看轻自己的人总是很知足,对获得的成功珍惜有加。一个人富有了,仍然不忘看轻自己,他将不会自傲和奢侈;一个人身居高位,仍然看轻自己,他将不会专横和贪婪。当你从困惑中走出来时,就会发现,看轻自己,其实是一种多么难得的境界:超凡脱俗,淡泊平和。
  看轻自己是人生的一种高品位的精神享受。看轻自己是对人的真实本性和历史真正趋向的理解和把握,是对人性和历史的继承和超越。看轻自己,能够成就人的操守,闪烁灵魂的美丽。只有看轻自己,并不断否定自己的人,才能够不断汲取教训、加强修炼、净化灵魂、提升品质,才会为别人的成功而欣喜,为自己的善解人意而高兴。
  把自己看轻,它并不是自卑,也不是怯弱,它是清醒中的一种经营。也不是鄙视自己,压抑自己,埋怨自己,也不要你去说违心话,做违心事。相反,看轻自己能使你更加清醒地认识自己。
  为人处世,不妨看轻自己,生活中就会多几分快乐。在家庭中,不妨看轻自己,不要把自己当成“一言九鼎“的家长,才能更好地与孩子沟通,与爱人和谐相处。在事业上,即使春风得意,大权在握,也不妨看轻自己,不要把自己当成众人之上的“楚霸王”。这样,才能结交更多志同道合的盟友,听取更多的有益于事业发展的意见,让自己脚踏实地去拓展事业,创造辉煌。在朋友圈子里,不妨看轻自己,才能结识到推心置腹的哥们儿,让自己时刻头脑清醒,让自己永远是一个受欢迎的朋友。把自己看轻,才能获得智慧与快乐,飞越坎坎坷坷,拥有和谐的人生。

同类题4

阅读理解

       When it comes to medical care, many patients and doctors believe “more is better.” But what they do not realize is that overtreatment—too many scans, too many blood tests, too many procedures—may bring harm. Sometimes a test leads you down a path to more and more testing, some of which may be invasive, or to treatment for things that should be left alone.

       Terrence Power, for example, complained that after his wife learned she had Wegener's disease, an uncommon disorder of the immune system, they found it difficult to refuse testing recommended by her doctor. The doctor insisted on office visits every three weeks, even when she was feeling well. He frequently ordered blood tests and X-rays, and repeatedly referred her to specialists for even minor complaints. Even when tests came back negative, more were ordered, and she was hospitalized as prevention when she developed a cold.   She had as many as 25 doctor visits during one six-month period. The couple was spending about $30,000 a year for her care.

       After several years of physical suffering and near financial ruin from the medical costs, the couple began questioning the treatment after discussing with other patients in online support groups. “It's a really hard thing to determine when they've crossed the line,” Mr. Power said. “You think she's getting the best care in the world, but after a while you start to wonder: What is the purpose?” Mr. Power then spoke with his own primary care doctor, who advised him to find a new specialist to oversee Mrs. Power's care. Under the new doctor's care, the regular testing stopped and Mrs. Power's condition stabilized. Now she sees the doctor only four or five times a year.