某研究小组为测定药物对体外培养细胞的毒性，准备对某种动物的肝肿瘤细胞（甲）和正常肝细胞（乙）进行动物细胞培养。下列有关说法正确的是（）

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小名

    大约我的出生与水有关，于是颇懂得斯文的外公顺口给我起名叫淼（mi3o）儿。在“淼儿、淼儿”的呼唤中我慢慢长大了，到了要上学的年龄时，爸爸觉得该有个体面的学名才对，便为我取了个挺大众化的名字，可家里人还是“淼儿、淼儿”地叫。特别是妈妈叫得尤为响亮频繁。

    不知为什么，随着年龄的增长，再听到家人唤我小名竟有些不舒服了，好像有一种不被尊重的感觉。终于有一天，我在听到妈妈又一声“淼儿”的呼唤后，郑重地对她说：“妈妈，我有大名的。别叫我小名好吗？”然后我在妈妈惊愕的表情里走进了自己的房间。

    但妈妈终究还是改不了。

    那天是我16岁生日聚会，好多同学都跑来了，家里的小客厅挤得满满的。我一边给大家分发糖果，一边忙不迭地说着谢谢。爸爸妈妈在厨房里忙着做菜，当一碟碟香气四溢的精美小菜端上餐桌时，同学萍将送给我的大蛋糕端了上来。我立刻连声称谢着打开了蛋糕盒。我喊道：“妈妈，拿刀子来！”

    妈妈一边递过来一把瓜刀，一边叮咛：“淼儿，小心点！”

    “咦！你原来叫淼儿呀，挺好玩的名字！”

    萍欢快地叫着，同时在空中打了一个别致的手势。朋友们也善意地哄笑起来，我的脸唰地红到了耳根。

    晚上，临睡觉时，我推开了妈妈的房门。倚着门框，又一次地对她说：“妈妈，我不是说过嘛，别叫我小名！”语气里已有了几分不耐烦。妈妈的脸上呈现出一种复杂的表情，看了走进来的爸爸一眼，叹了口气：“对不起！高翔！”可我听出我的名字在她口中变得十分生硬，似乎很绕口。

    没多久，我要离开家到数百里外的一座城市去读书。

    不知怎的。妈妈竟在短短的几天内学会了很有味地叫我的大名，而且同以前叫我小名时那样顺口熟练。我自然很高兴。

    分别的那一天，爸妈一起送我去车站，爸爸一直喋喋地叮三嘱四，妈妈则沉默着，显得有些黯然。我大人似的笑笑，反过来抚慰着他们：“放心吧，没事的，我已不是孩子了。”

    火车开动的刹那，我从车窗探出头去，同他们挥手告别，一直不言不语的妈妈突然抬起了头，眼里竟有了泪。她追着，跑着，挥动双手，脱口喊了出来——   

    “写信回来。淼儿！”

    我稍稍一愣，心里似乎被什么东西猛撞了一下，渭水夺眶而出。

若{a_n}为递减数列，则{a_n}的通项公式可以为（  ）

阅读理解

    Author Elizabeth Becker says we have a responsibility to respect the places we visit. Some basic rules still hold, such as not travelling at busy times and taking fewer trips but making them longer. The best and easiest way to be a responsible traveler is to use common sense and go local.

    Respect traditions. Read about the culture and traditions of the places you visit. Understand the local culture and customs to avoid making any mistakes or upsetting the local people. For example, dress properly when you visit temples and don’t eat or talk loudly in religious(宗教的)sites. It’s also important to respect the local environment. If you visit a beach, leave seashells where you find them and try not to catch fish while swimming.

    Learn the language. Nobody expects you to become fluent, but try to learn some basic phrases such as “please” and “thank you”. You’ll be amazed at how much nicer and more helpful people will be if they know you’re making an effort to get involved with their culture.

    Spend local. Stay away from international hotels and restaurants run by foreigners. By using local guides, buying local products and staying in family run hotels, you’re not only giving back to the community, but you also get a real sense of the country you’re staying in and the people who live there.

    Bargain fairly. Always be polite when you try to get a lower price. Sometimes goods at a local market can seem overpriced. Nobody likes to be cheated and it may be fun to bargain, but remember that for the local people bargaining it may not be a game. For some of them, their business is their only source of income. So try not to be too rude when bargaining.

    Don’t litter. In some countries, getting rid of waste is a big problem, so don’t throw rubbish on the ground. Doing so is harmful to the environment and unpleasant for others. Hold on to your rubbish until you find a bin.

    Save water. Even in some of the most developed countries, water shortages are a reality. Tourists who take 10-minute showers and leave the taps running aren’t making things any better.