在细胞免疫中，效应T细胞发挥免疫作用的机制是：

购物广场内甲、乙两家商店对A，B两种商品均有优惠促销活动；

甲商店的促销方案是：A商品打八折，B商品打七五折；

乙商店的促销方案是：购买一件A商品，赠送一件B商品，多买多送。

请你结合小明和小华的对话，解答下列问题：

正方体的表面积可以表示为（  ）

        A high school history teacher once told us, “If you make one close friend in school, you will be most fortunate. A true friend is someone who stays with you for life."1 teaches that he was right. Good friendship is just not easily 2

        It is possible that we simply do not stay in one place long enough food 3friendship to4. However, there can be5disagreement on the need for each of us to think carefully about the kind of friendship we want.

        To most of us, friendships are considered very important, but we need to have clear in our 6 the kinds of friendship we want. Are they to be close or7at arm's length? Do we want to 8ourselves or do we want to walk on the surface? For some people, many friendships on the surface are 9enough—and that' s all right. But at some point we need to10that our expectations are the same as our friends' expectations. The sharing of11experience 12our tears as well as our dark dreams is the surest way to deepen friendships. But it 13be undertaken(进行) slowly and carried on only if there are 14of interest and action in return.

          What are some of the 15of friendship? The greatest is the attraction to expect too much too soon. Deep relationships 16time. Another“major difficulty" is the selfishness to think one “possesses" the other, including his time and attention. Similarly, friendships 17actions in return. In 18words, you must give as much as you take. Finally there is a question of taking care of. Unless you spend 19time together, talking on the phone, writing letters, doing things together, friendships will die20.

依次填入下列横线处的词语，最恰当的一组是(    )
(1)并不是每一个人的家乡都有历史悠久的名胜古迹或是风景秀丽的观光胜地。但家乡的山水__________以她特有的姿态，出现在人们面前。
(2)在福州马尾区元宵灯会上，游客能有机会__________由马祖的台湾美食厨艺代表团和马尾的福州风味美食代表团献上的两岸美食。
(3)我希望“你摊上事儿了”不仅成为最新流行语，而且能__________那些有“事儿”的人，让那些没事找事的人不敢轻易生事。