阅读下列短文，根据短文内容，从短文后各题所给的A、B、C、 D四个选项中，选择最佳选项。

Are you shy? If you are, you are not alone. In fact, close to 50 percent of people are shy. Almost 80 percent of people feel shy at some point in their lives. These days, shyness is becoming more and more common. Now, scientists are trying to understand shyness. They have some interesting ideas about why people are shy.

Is it possible to be born shy? Many scientists say yes. They say 15 to 20 percent of babies behave shyly. These babies are a little quieter and more watchful than other babies. Interestingly, these shy babies usually have shy parents. As a result, scientists think that some shyness is genetic.

Family size might cause people to be shy as well. Scientists at Harvard University studied shy children. They found that 66 percent of them had older brothers and sisters. As a result, they became shy. At the same time, children with no brothers and sisters may be shy as well. Growing up alone, they often play by themselves. They are not able to learn the same social skills as children from big families.

You may also be shy because of where you were born. When scientists studied shyness in different countries, they found surprising differences. In Japan, most people said they were shy. But in Israel, only one of three people said so. What explains the difference? One scientist says the Japanese and Israelis have different opinions of failure. In Japan, when people do not succeed, they feel bad about themselves. They blame（责备）themselves for their failure. In Israel, the opposite is true. Israelis often blame failure on outside reasons, such as family, teachers, friends, or bad luck. In Israel, freedom of opinion and risk taking are strongly supported. This may be why Israelis worry less about failure and are less shy.

For shy people, it can be difficult to make friends, speak in class, and even get a good job. But scientists say you can get over your shyness. They suggest trying new things and practicing conversation. And don't forget---if you are shy, you are not the only one.

阅读下面的古诗文，完成 后面小题。

（一）

       钱镠，临安石鉴乡人。及壮，以贩盐为生。县录事钟起有子数人，与镠游，起时时贷其穷乏。唐僖宗时，平浙寇王仙芝，拒黄巢，灭董昌，积功自显。梁开平元年，封镠为吴越王①。有讽镠拒梁命者，镠笑曰：“吾岂失一孙仲谋耶！”遂受之。镠还乡，一邻媪九十余，携壶泉迎于道左。镠下车亟拜。媪抚其背，以小字呼之曰：“钱婆留，喜汝长成。”盖初生时光怪满室，父惧，将沉于溪。此媪苦留之，遂字焉。为牛酒②大陈，以饮乡人。镠起劝酒，自唱还乡歌以娱宾。

       注释：①吴越王：钱镠因中原强大，依附梁国所获的封号。②牛酒：即牛和酒，古代用来犒劳、祭祀。

（二）

       淮阴侯韩信者，淮阴人也。始为布衣时，数从亭长寄食，数月。亭长妻患之，乃晨炊蓐食①。食时信往，不为具食。信亦知其意，怒，竟绝去。信钓于城下，诸母漂②，有一母见信饥，饭信数十日。淮阴屠中少年有侮信者，曰：“信能死③，刺我；不能死，出我胯下。”于是信孰视之，俯出胯下，一市人皆笑信，以为怯。

       汉五年正月徙齐王信为楚王都下邳信至国召所从食漂母赐千金。及下乡南昌亭下，赐百钱，曰：“公，小人也，为德不卒。”召辱已之少年令出胯下者，以为楚中尉。告诸将相曰：“此壮士也。方辱我时，我宁不能杀之邪？杀之无名④，故忍而就于此。”

       注释：①晨炊蓐食：提前做好早饭，端到室内床上吃掉。②母：对老年妇女尊称。漂：在水里冲洗丝棉之类。③能死：不怕死。④无名：没有意义。

等比数列前$n$项和为54，前$2n$项和为60，则前$3n$项和为（ ）

阅读短文，回答问题：

    电热膜是一种新型的电热器件，如图甲所示是一种常见的电热膜．电热膜是在绝缘的聚酯薄膜表面，经过特殊工艺加工形成的一条条薄的导电墨线，导电墨线两端与金属导线相连，形成网状结构，其内部结构如图乙所示．

    电热膜通电工作时没有发红、炽热现象产生，它与被加热物体直接接触，产生的热量很快传给被加热物体，所以电热膜本身温度并不太高，不易氧化，使用寿命长．在制造电热膜时，会出现不同区域导电墨线厚度不均匀的现象，厚的导电墨线电阻小．导电墨线电阻随温度变化的关系如图丙所示，这种温度特性的优点是，它不会因厚度不均匀而出现严重发热不均、局部过热的现象，这是电热丝所不具备的，它保证了电热膜各处的温度均匀．

（1）电热膜取暖器工作时，室内空气温度升高是通过____ 方式增加空气内能的；

（2）某根导电墨线的局部导电材料脱落，如图丁中A部分，这根导电墨线的电阻____ ；

A．变大　　　　 B．变小　　　　 C．不变　　　　 D．以上三种情况均有可能

（3）与传统的电热丝加热器相比，电热膜取暖器的发热效率高，原因是____ 

（4）将图戊中一块电热膜接入电路，正常工作时金属导线中A、B处电流分别为I_A和I_B，则I_A____ I_B；（填“＜”、“=”或“＞”）

（5）电热膜不会因厚度不均而出现局部过热的现象，原因是____