She is currently rated number two in the world.

　　她目前排名世界第二。

　　The two groups of children have quite different characteristics.

　　這兩組兒童具有截然不同的特點。

　　The child disappeared from his home some time after four.

　　這孩子四點多的時候就離家不見了。

　　She asked her students to get into groups of four.

　　她讓學生每四人分為一小組。

　　First get students to form groups of four.

　　首先讓學生分成四人一組。