在下述生物中，哪种可用于高等植物的基因转移工作        （  ）

现代文阅读

                                                                                             《我的母亲》（节选）
                                                                                                          胡适
        家里虽然一贫如洗，但母亲情愿节衣缩食，省下钱来请了一位先生。我到十岁的时候，读的是“孟子见梁惠王”。到年底，父亲要“清算”我平日的功课。在夜里亲自听我背书，很严厉，桌上放着一根两指阔的竹板。我背向着他立着背书，背不出来的时候，他提一个字，就叫我回转身来把手掌展放在桌上，他拿起这竹板很重地打下来。我吃了这一下苦头，痛是血肉的身体所无法避免的感觉，当然失声地哭了，但是还要忍住哭，回过身去再背。不幸又有一处中断，背不下去；经他再提一字，再打一下。呜呜咽咽地背着那位前世冤家的“见梁惠王”的“孟子”！我自己呜咽着背，同时听得见坐在旁边缝纫着的母亲也唏唏嘘嘘地泪如泉涌地哭着。我心里知道她见我被打，她也觉得好像刺心的痛苦，对我表着十二分的同情，但她却时时从呜咽着的、断断断续续的声音里勉强说着“打得好”。她的饮泣吞声，为的是爱她的儿子；勉强硬着头皮说声“打得好”，为的是希望她的儿子上进。如今想起母亲见我被打，陪着我一同哭，那样的母爱，仍然使我感念着我的慈爱的母亲。背完了半本“梁惠王”，右手掌被打得发肿，有半寸高，偷向灯光中一照，通亮，好像满肚子装着已成熟的丝的蚕身一样。母亲含着泪抱我上床，轻轻把被窝盖上，向我额上吻了几吻。
        当我八岁的时候，二弟六岁，还有一个妹妹三岁。三个人的衣服鞋袜，没有一件不是母亲自己做的。她还时常收一些外面的女红来做，所以很忙。记得有一个夏天的深夜，我忽然从睡梦中醒了起来，因为我的床背就紧接着母亲的床背，所以从帐里望得见母亲独自一人在灯下做鞋底，我心里又想起母亲的劳苦，辗转反侧睡不着，很想起来陪陪母亲。于是想出一个借口来试试看，便叫声母亲，说太热睡不着，要起来坐一会儿。出乎我意料之外的，母亲居然许我起来坐在她的身边。我眼巴巴地望着她额上的汗珠往下流，手上一针不停地做着布鞋——做给我穿的。这时万籁俱寂，只听得嘀嗒的钟声和可以微闻得到母亲的呼吸。我心里暗自想念着，为着我要穿鞋，累母亲深夜工作不休，心上感到说不出的歉疚，又感到坐着陪陪母亲，似乎可以减轻些心里的不安。当时一肚子里充满着这些心事，却不敢对母亲说出一句。现在我的母亲不在了，她始终不知道她这个小儿子心里有过这样的一种不敢说出的心理状态。

阅读下面材料，在空白处填入适当的内容（不多于3个单词）或括号内单词的正确形式。

    Not all memories are sweet. Some people spend all their lives trying to forget bad experiences.

    Now American researchers think they are close to developing a pill, ____ will help people forget bad memories. The pill is designed ____ (take) immediately after a frightening experience. They hope it might reduce, or ____ (possible) erase (抹去) the effect of painful memories.

    In November, experts tested a drug on people in the U.S. and France. The drug stops the body from ____ (release) chemicals that fix memories in the brain. So far, the research ____ (suggest) that only the emotional effects of memories may be reduced, not that memories are wiped out. They are not sure to the degree people's memories are affected.

    The research has caused a great deal of ____ (argue). Some think it is ____ bad idea, while others support it. Supporters say it could lead to pills which prevent or treat soldiers' troubling memories after war. They say that there are many people who suffer from terrible memories. ____, those who are____ the research say that maybe the pills can change people's memories and changing memories is very ____ (danger) because memories give us our identity.