题干

通过细胞杂交,要获得一个杂种植株,需要哪些步骤                                    (    )

A:分离原生质→诱导原生质融合→组织培养方法→得到杂种植株

B:分离原生质→原生质融合→杂种植株

C:获取细胞→原生质融合→组织培养→杂种植株

D:获得细胞→原生质直接融合→组织培养→杂种植株

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A

同类题1

阅读理解。阅读下列短文,根据短文内容选择最佳答案。

    Would you believe that the first outstanding deaf teacher in America was a Frenchman? His name was Laurent Clerc. He became a friend of Thomas Hopkins Gallaudet and together they founded America's first school for the deaf.

    Laurent Clerc was born in a small village near Lyons, France, on December 26, 1785. When he was one year old, he fell into a fire, losing both his hearing and his sense of smell.

    At 12, Laurent entered the Royal Institution for the Deaf in Paris where he did well in his studies. After he graduated, the school asked him to stay on as an assistant teacher.

    Meanwhile, in America, Thomas Hopkins Gallaudet was studying to be a minister. He was very concerned about the lack of educational opportunities for the deaf. Therefore, in 1815, Gallaudet sailed to London, England to seek ideas on how to teach deaf people. While he was there, he met a French educator of the deaf who invited him to go to Paris to spend three months learning at the Royal Institution for the Deaf, the school where Laurent Clerc was teaching. Gallaudet accepted the offer. The two worked and studied well together. When the time came for Gallaudet to return, he asked Clerc to come with him. Clerc accepted on one condition: that he would stay in America only a short time.

    The two men set sail on June 18, 1816. The voyage across the Atlantic Ocean took 52 days; however, Clerc and Gallaudet put the time to good use. Clerc studied English, and Gallaudet studied sign language. They discussed the school for the deaf which they planned to open. On the long trip, they had many conversations about education and deafness. The year after they arrived, they founded a school for the deaf in Harford, Connecticut.

At the school, Clerc led a busy life. He taught signs to Principal Gallaudet; he taught the pupils; and he taught hearing men who came to the school to study deaf education.

    In 1819, Clerc married Eliza Crocker Boardman, one of his pupils. They had six children. He retired from teaching in 1858. Although he had intended to return to France, he never did. He died on July 18, 1869 in the United States.

同类题2

阅读下文,回答问题

宁静是一种生产力

于丹

    ①清人张潮在《幽梦影》中写道:“能闲世人之所忙者,方能忙世人之所闲。”这句话颇有意味,意思是指大家都在忙碌的事情,你能够悠闲地对待它,才会有时间、有心思去满足自己的闲情逸趣。

    ②别人忙碌追逐的你不追赶,别人置之不理的你用心去体会。这是一个发现的过程。发现什么呢?发现一种生活方式,发现生命的质量。《菜根谭》里说:“性躁心粗者一事无成,心平气和者百福自集。”讲的是同样的道理。

    ③宁静有时也是一种生产力。一个人能够平心静气,就能够获得一种智慧的能量,提高生命的质量和效率。

    ④我曾经看过一个小故事。一位木匠把手表掉在半人高的刨花里,让众多徒弟去找,大家乱哄哄地找,怎么也找不着。后来他的儿子独自在夜里静静地听手表走动的响声,始终找到那块手表。事情很简单,道理却很深刻。想想看,宁静难道不是一种生产力吗?

    ⑤《庄子》中说:“水静犹明,而况精神!圣人之心静乎!天地之鉴也;万物之镜也。”天地万物是可以映照在我们心中的,前提是心要安静。喧嚣的小溪把碎沫拍打在山崖上的时候,澎湃的大海把浪花摔打在沙滩上的时候,它能照见世界吗?它什么也看不见。

    ⑥一个人的心里有太多欲望,过分在意他人的赞誉和诽谤之语,这颗心就会像喧嚣的小溪碎沫和澎湃的大海浪花,鼓动着,躁动着,这样的人能静下来吗?如果不能拥有一份宁静,不能拥有一种闲适,我们能看见生命的本真吗?

    ⑦安静下来,在中国人本来的生命规律中去发现悠然的欢喜,对今天这个时代而言,也许不仅是一件锦上添花的事,说它是雪中送炭也不为过。

(选自《趣品人生》,有删改)