Many Chinese students find it hard to learn English, but not Chinse, because Chinese is their mother tongue.1，Chinese is much more diffcult to learn than English.

    Still some students in other countries can speak Chinese very2  If you don't see them, you may think they are Chinese.What3them learn Chinese so well?

    “For me,conversation is really helpful,I try to speak in4.If you only listen to what others speak,you will be good at5But if you talk as much as you6,you will find you can speak good Chinese. ”says Jenny Brown,a girl from Canda Now she is7Chinese at Peing University.She is interested in China and8history.She thinks that to learn a language, one must try to know9about the country.

    Chinese is10from English, but we can use the same way in leamning it."

物体从高处自由下落，若选地面为参考平面，则下落时间为落地时间的一半时，物体所具有的动能和重力势能之比为 （       ）