胸腔穿刺抽液不宜过多过快的主要目的是为了防止A．蛋白丢失过多B．自发性气胸C．纵隔复

根据短文内容判断下列句子的正(√)误(×)。

      It's sunny on Sunday morning. There are many people in the park. They are having fun together. Some

are playing games under a big tree. Some are climbing the hill. Others are rowing on the lake. John is reading

a book in front of the house. Lucy is playing with a ball. Becky and Flower are singing. Kate and Ann are

dancing beside the tree.

( ) 1. There are a lot of people in the zoo.

( ) 2. Many people have a good time.

( ) 3. John is reading a book.

( ) 4. Kate and Ann are dancing behind a tree.

( ) 5. Lucy and Flower are singing.

钻井工程对钻井液的要求，其中之一就是确保（）。

A、失败

B、安全

C、破坏

D、危险

组织文化的类型根据美国哈佛大学教授泰伦斯·迪尔及麦肯锡管理咨询公司顾问艾伦·肯尼迪提出的理论，可以分为（）

A.硬汉式文化

B.“拼命干、尽情玩”文化

C.攻坚文化

D.过程文化

E.服务文化

F.群体文化

美国最早的证券交易所是（）。

A．纽约证券交易所

B．芝加哥证券交易所

C．费城证券交易所

D．波士顿证券交易所

试述咬边产生的原因？