大黄粉末升华物，低温有（）结晶，高温有羽状结晶。

Facebook is one of the most popular websites that offer social networking today with more than l billion users around the world. Online social networking is just like-minded people coming together for some activities, forming groups, having discussions, sharing photographs, etc. Similarly, Facebook enables all these activities by various applications(运用程序) , for example, providing forums, photo sharing options. video updating, keeping a track on all the happenings in their formed communities, people they have approved to be linked to, etc. Online gaming is one of the biggest USPs(独特的卖点) of Facebook, and indeed, games like Farmville and Mafia Wars have attracted many users to the site. Facebook also offered a brilliant platform for business to reach out to their customers.

In the beginning, Facebook was just meant for Harvard University students to find and contact fellow students. It was meant to serve the purpose of keeping track of who was new to college to get in touch with each other for project purposes.  It was an online directory(目录) , and was founded in 2004 0n the Harvard University campus. However, as soon as it was launched, almost two thirds of the total number of students registered themselves on Facebook. Mark Elliot Zuckerberg, along with Chris Hughes, Dustin Moskovitz. and Eduardo Saverin. helped in the launch of the site. To pursue this, Mark dropped out of Harvard and got into making Facebook a worldwide accessible site, and then to its current stand of being the top social networking site in the world.

Today, Facebook rules the social networking world, with one person in fourteen using it. It is also the second most popular site in the US, and is worth billions of dollars. And it has been a success story for the four co-founders, making them all accidental billionaires.

Title :  Facebook-the most popular social networking site in the world

I . Definition :

*One popular website    小题1:   

Ⅱ.   小题2:  :

* Enabling people to gather for  小题3:    0n it

*   小题4:   

* Offering a brilliant platform for businesses to reach out to their customers

Ⅲ   Birth :

* Time: in 2004

* Place:    小题5:

lV.    小题6:  :

* To help students contact each other

V.   小题7:   :

* Mark Elliot Zuckerberg, along with Chris Hughes, Dustin Moskovitz, and Eduardo Saverin

VI. Popularity:

* As an     小题8:    : having almost two thirds of the students on it

* As the top social networking site :

ruling  the social networking ;

having over    小题9:    in the world;

being    小题10:    billions of dollars

用热电偶温度计测铅液温度，铅液温度控制在______内。

A．400～500℃

B．600～650℃

C．650～750℃

D．750～900℃

在项目融资中一般需要( )。

A．抵押担保

B．质押担保

C．保证贷款

D．严谨的担保体系

已知两种分子A和B反应生成另外两种分子C和D，则下列判断不正确的是

A．A物质属于氧化物

B．D物质HClO中氯元素的化合价为 +1价

C．这是一个置换反应

D．反应前后元素的种类和原子个数不变

常用冷却空气的蒸发器分为什么？