小丽想用一块面积为400cm2的正方形纸片，沿着边的方向裁出一块面积为300cm

某居民房发生火灾，房内居住的妻子和小孩死亡，丈夫王某没有受伤。经勘查，起火部位的卧房内床铺下部燃烧重于上部，床前水泥地面上有液体流淌燃烧痕迹，经提取物证检测，鉴定结论为汽油。房间门窗完好，现场无爆燃痕迹，周围群众未听到爆炸声响，房间内无处于工作状态的用电设备。经讯问，王某承认夫妻间发生口角，他一时激动将平时放置于室外的汽油桶拿进房间并将汽油倒在床前地面上，但未实施点火行为，过了几分钟其站在门口抽烟，将燃着的烟蒂扔在地上时起火；在后来的讯问中又改口称是过了几分钟站在门口用打火机点烟时引起火灾。

分析以上案情，回答下列问题：

其他条件相同，汽油在空气中的浓度（）时，发生爆燃时的破坏程度最严重。

A、接近爆炸上限

B、接近爆炸下限

C、接近爆炸上限、下限的平均值

D、稍高于化学计量浓度

免疫球蛋白lgG的结构示意图如下，其中—S—S表示连接两条相邻肽链的二硫链。若该lgG由m个氨基酸构成，则该lgG有肽键数

A．m个

B．(m+1)个

C．(m-2)个

D．(m-4)个

根据有关规定，我国基金管理公司主要股东的注册资本不得低于人民币（）。

A.5亿元

B.3亿元

C.2亿元

D.1亿元

阅读理解。

     Visitors to Britain may find the best place to sample local culture is in a traditional pub. But these friendly

pubs can be dangerous places of potential gaffes (失礼) for the newcomers.

     A team of researchers have discovered some of the unknown customs of British pubs-starting with the

difficulty of getting a drink. Most pubs have no waiters-you have to go to the bar to buy drinks. A group of

Italian youths waiting 45 minutes before they realized they would have to fetch their own. This may sound

inconvenient, but there is a hidden purpose.

     Pub culture is designed to promote sociability (社交) in a society known for its reserve. Standing at the

bar for service allows you to chat with others waiting to be served. The bar counter is possibly the only site

in the British Isles in which friendly conversation with strangers is considered entirely suitable and really quite

normal behavior. "If you haven't been to a pub, you haven't been to Britain." This tip can be found in a booklet,

Passport to the Pub: The Tourists' Guide to Pub Etiquette, a customers' rule of conduct for those wanting to

sample "a central part of British life and culture".

     The trouble is that if you do not follow the local rules, the experience may fall flat. For example, if you are

in a big group, it is best if only one or two people go to buy the drinks. Nothing annoys the regular customers

and bar staff' more than a group of strangers blocking all access to the bar while they chat and hesitate about

what to order.

1. The underlined word "sample" in the first paragraph probably means "_____".

A. taste

B. experience

C. test

D. record

2. The culture of pub in Britain is developed to _____.

A. encourage people to communicate with each other

B. encourage more people to consume drinks

C. attract more tourists to the pubs

D. form its own character of culture

3. If you don't follow the local rules in a pub, _____.

A. you won't buy good local drinks

B. you may annoy the regular customers and bar staff

C. you may fail to feel the local culture

D. you might get into a dangerous place

4. What may be the best title for the passage?

A. Self-service Pubs in Britain

B. British Local Pubs: Special Chat Places

C. Local Pub Culture in Britain

D. Manners in British Local Pubs

目前人们对企业社会责任的认识依旧比较（），看不到自己行为造成的后果。

A．浮浅

B．肤浅

C．浅薄

D．浅显