已知图中阴影部分的面积和正方形面积的比是4∶9，正方形边长是6cm，求图中阴影部分的面积。

____平方厘米

在人体内，具有保护、分泌等功能的组织是

    There are many ways for us to learn English. Different people have different ways. But I think the best way to learn English is1it. Do you 2 with me?

    Listening, speaking, reading and writing are all very3 in learning English. So we should learn the four English skills. While learning English, we need to4 many words, grammar(语法)rules and know about 5cultures. Some people learn English by listening to the 6 or watching TV. They try to 7 English with their friends every day. You don't need to care how badly you speak. The more you speak, the better your English will become. Some people go to the English corner to 8English. They also read English storybooks very often. When they meet a new word，they will look it up (查阅) in 9 You should also practice 10 in English every day.

    Keep trying and working hard to improve your English.

在10个球中有6个红球和4个白球（各不相同），不放回地依次摸出2个球，在第一次摸出红球的条件下，第2次也摸到红球的概率为（  ）