洗舱作业时，人员下舱作业的要求是（）。A.可燃气体浓度≤LEL2% B.氧气浓度≥2

Which is the most popular song in the world now? Yes, it’s South Korean star PSY’s “Gangnam style” video. The video has become the most liked video on YouTube.

In fact, breaking records, the video has set the Guinness (吉尼斯) World Record for the most 'liked' video in YouTube history. Gangnam Style, that was available for viewing on July 15, has more than 2,479,030 likes on YouTube. What’s catching the eyes in Gangnam style is PSY’s special dance moves, funny horse riding scenes and dancing in a towel（毛巾）. Even as many may not understand the language, the video has become the talk of the Internet.

The video also has many different versions（版本） on the Internet now. The song has been the top one on the song lists in 31 countries, including the United States, United Kingdom, and Canada. “The YouTube video never wanted to attract foreign countries. It was for local fans,” PSY told the reporters after a concert. “My goal in this music video was to look not so fashionable until the end. I achieved it. ”

The singer’s stage name is from “psycho”, and he writes and produces his own music. “Gangnam style” is about the lifestyle of the young people in Seoul, the Capital of South Korea.

小题1:Who sang the song “Gangnam Style” first?

A．YouTube.

B．PSY.

C．Guinness.

D．We don’t know.小题2:YouTube is probably a ___________.

A．magazine

B．newspaper

C．shop

D．website小题3:So many people are interested in PSY’s special dance moves. It looks like___________.

A．duck walking

B．fish swimming

C．horse riding

D．bird flying小题4:The song won the first place on the song lists in ___________ countries.

A．about thirty

B．three

C．fifteen

D．millions of小题5:Which of the following is TRUE according to the passage?

A．PSY is the singer’s real name.

B．PSY sings songs written by others.

C．The song of “Gangnam style” appeared in mid-July.

D．“Gangnam Style” describes the lifestyle of the old people in Seoul.

基站（BS）发射机射频发射频率偏差应小于或等于（）。

A.5.00E-10

B.5.00E-07

C.1.00E-08

D.5.00E-08

下表是元素周期表的一部分。表中所列的字母分别代表一种化学元素。

试回答下列问题：

（1）请写出：元素o的基态原子电子排布式_________ 

（2）k在空气中燃烧产物的分子构型为     ，中心原子的杂化形式为    ，该分子是  （填“极性”或“非极性”）分子。

（3）含10电子的d的氢化物分子的VSEPR模型为_______。元素c、a、e按原子个数1：2：1组成生活中常见有甜味分子，该分子中有___个手性碳原子。

（4）g、h、i三种元素的第一电离能由大到小的顺序为________（填元素符号）

(5) 所有元素 其中电负性最大的是___（填图中的序号或元素符号），元素k有两种氧化物，它们对应的水化物的酸性强弱顺序为__________；(填化学式)

秦代小篆的代表作品有哪些？

Mallory磷钨酸苏木精（PTAH）染色法用于显示（）

A.横纹肌纤维

B.平滑肌纤维

C.胶原纤维

D.弹性纤维

E.神经纤维