①双曲线 $\frac{y^2}{9}$ ﹣ $\frac{x^2}{4}$ =1的渐近线方程是y=± $\frac{2}{3}$ x；

②若点（2，3）在焦距为4的双曲线 $\frac{x^2}{a^2}$ ﹣ $\frac{y^2}{b^2}$ =1上，则此双曲线的离心率e=2；

③若点F，B分别是双曲线 $\frac{x^2}{a^2}$ ﹣ $\frac{y^2}{b^2}$ =1的一个焦点和虚轴的一个端点，则线段FB的中点一定不在此双曲线的渐近线上．

其中正确命题的个数是（　　）

多音字组词

难 nán____ nàn____  着 zháo____ zhuó____夹jiā ____ jiá____ gā ____                      

根据短文内容，选择正确答案。

Every four years, the greatest athletes from all over the world get together in one city to take part in the world sports meeting—the Olympic Games. The holy flame (圣火) is carried from one place to the next. In 2008, the holy flame was carried to Beijing, the capital of China.

When Beijing was chosen as the host city to hold the Olympic Games in 2008, all the Chinese people were very happy, excited and proud. They showed their excitement in different ways when they heard the news. Some people cheered, jumped and shouted.

    In Beijing we built a new Olympic village with hotels for athletes and stadiums for matches.

    "One World, One Dream" is our slogan for the 29th Olympics. It expresses the wishes of 1.3 billion Chinese people for a peaceful and better world tomorrow.

—Can I ______your dictionary?                          
—Sorry，I'm using it.

《中国对外开放的伟大实践》一文中提到：“十年实践，在我国沿海建立了从南到北的包括2个直辖市、25个省辖市、67个县、约1．5亿人口的对外开放前沿地带。”此后，我国政府（    ）