已知函数f（x）=sin（πx+ $\frac{\pi }{4}$ ）和函数g（x）=cos（πx+ $\frac{\pi }{4}$ ）在区间﹣ $\frac{9}{4}$ ， $\frac{3}{4}$ 上的图象交于A，B，C三点，则△ABC的面积是（   ）

某有机物6.0g在空气中完全燃烧，共得到17.6g二氧化碳和10.8g水，则该化合物的组成元素是（   ）

先通读下面的短文，掌握其大意，然后从A、B、C、D四个选项中选择可以填入空白处的最佳答案。    Do you have a good friend? I have one. She's English and1name is Kate.We are in the same (相同的)2and my desk is next to hers.She is nice and I3her well.She always4me with my English and I always tell her how to say "quilt", "grandma", "radio" …in Chinese.She likes reading and she has so many5in her room.They are everywhere — on her bed, on the sofa and on her desk ...Some of them are6the computer.She7it's very important(重要的).Look! This is a8of Kate's family.9people(人)are in it：her parents.her sister, her brother and herself(她自己).Kate's mother Helen is our English10.She teaches well and she's good to us.We like her very much.

如图所示的Venn图表示了集合A，B，U之间的关系，则阴影部分表示的是（   ）