题干

下列哪一种生物不是由一个细胞构成的(  )

A:酵母菌

B:海带

C:草履虫

D:变形虫

上一题 下一题 0.0难度 选择题 更新时间:2019-08-10 08:25:32

答案(点此获取答案解析)

B

同类题4

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    先帝虑汉、贼不两立,王业不偏安,故托臣以讨贼也。以先帝之明,量臣之才,故知臣伐贼,才弱敌强也。然不伐贼,王业亦亡。惟坐而待亡,孰与伐之?是故托臣而弗疑也。臣受命之日,寝不安席,食不甘味;思惟北征,宜先入南。故五月渡泸,深入不毛,并日而食。臣非不自惜也,顾王业不可偏安于蜀都,故冒危难以奉先帝之遗意。而议者谓为非计。今贼适疲于西,又务于东,兵法乘劳,此进趋之时也。谨陈其事如左:

    高帝明并日月,谋臣渊深,然涉险被创,危然后安。今陛下未及高帝,谋臣不如良、平,而欲以长计取胜,坐定天下,此臣之未解一也。刘繇、王朗,各据州郡,论安言计,动引圣人,群疑满腹,众难塞胸,今岁不战,明年不征,使孙策坐大,遂并江东,此臣之未解二也。曹操智计,殊绝于人,其用兵也,仿佛孙、吴,然困于南阳,险于鸟巢,危于祁连,逼于黎阳,几败北山,殆死潼关,然后伪定一时耳,况臣才弱,而欲以不危而定之:此臣之未解三也。曹操五攻昌霸不下,四越巢湖不成。任用李服,而李服图之;委任夏侯,而夏侯败亡。先帝每称操为能,犹有此失;况臣驽下,何能必胜?此臣之未解四也。自臣到汉中,中间期年耳,然丧赵云、阳群、马玉、阎芝、丁立、白寿、刘邰、邓铜等,及曲长、屯将七十余人,突将无前。丛、叟、青羌,散骑武骑一千余人,此皆数十年之内所纠合四方之精锐,非一州之所有;若复数年,则损三分之二也。当何以图敌?此臣之未解五也。今民穷兵疲,而事不可息;事不可息,则住与行劳费正等,而不及今图之,欲以一州之地,与贼持久,此臣之未解六也。

    夫难平者,事也。昔先帝败军于楚,当此时,曹操拊手,谓天下已定,然后先帝东连吴越,西取巴、蜀,举兵北征,夏侯授首。此操之失计,而汉事将成也。然后吴更违盟,关羽毁败,秭归磋跌,曹丕称帝。凡事如是,难可逆见。臣鞠躬尽瘁,死而后已;至于成败利钝,非臣之明所能逆睹也。

【注】①王业不偏安:帝王的事业不能自安于蜀地一隅。②思惟北征,宜先入南:考虑着要想北征魏国,应先平定南中诸部,以巩固后方。③非计:不正确的计策。④今贼适疲于西:此指公元228年,诸葛亮出祁山伐魏而言。⑤又务于东:指同年八月东吴陆逊战败魏将曹休。务,勉力从事。⑥进趋:赶快进兵。⑦坐大:安然地强大起来。⑧拊手:拍手(称快)。⑨秭归磋跌:刘备因孙权击杀关羽,兴兵伐吴,公元222年至秭归为吴军所败。磋跌,失足跌倒,比喻失败。⑩逆见:预料。⑾利钝:顺利和困难。⑿逆睹:预料。

同类题5

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    A dog, it is said, is a man's best friend. Put a dog, a kid and a book together, and you have a struggling reader's best friend.

    The therapy dogs of R.E.A.D. – Reading Education Assistance Dogs – have been helping children improve their reading skills since 1999, when Intermountain Therapy Animals (ITA) began the program in Salt Lake City, Utah.

    Today, tens of thousands of R.E.A.D. teams – dogs and their owners – volunteer to spend time with youngsters in schools and libraries across the United States and around the world. The idea is that sharing a book with a nonjudgmental (不带评论的) partner encourages students' confidence and helps develop a love of reading.

    Izzy, a Havanese therapy dog, is a regular visitor to Public School 57 in East Harlem, New York. Students meet him in the library, pick out a book and sit down on the carpet. Izzy snuggles (依偎) up to them and gets ready to hear a story.

    “I love reading to Izzy because he listens to me, and he doesn't make fun of me when I make a mistake,” says third-grader Aelane Vasquez. The 9-year-old, whose parents are from Mexico, is one of 15 Latin-American students at the school who were selected for the program.

    “All the students that we work with in the R.E.A.D. program were behind reading levels at the beginning of the year,” Bridget McElroy, who teaches English as a Second Language, explained. “Now most of them have reached the average level, if not above it.” That's important, because achieving proficiency (熟练) in reading is vital for kids to succeed. Studies have shown that students who can't read at grade level by the end of third grade are four times less likely to graduate high school by the age of 19.

    The R.E.A.D. teams from New York Therapy Animals work with 175 kids at Public School 57 and nine other schools.

    McElroy said she sees a marked difference in Aelane and her classmates, and not just in study. “Not only do the kids have time to practice reading, what we are really seeing is that they are excited to read and practice even when Izzy is not here,” she said.