一个正偶数的算术平方根是a，那么与这个正偶数相邻的下一个正偶数的算术平方根是（    ）

阅读下面材料，在空白处填入适当的内容（不多于3个单词）或括号内单词的正确形式。

        You may like reading novels for fun. But you need to get____(organize) if you are reading a novel for school. Here ____(be) a few tips.

        First, pay attention to characters. What do they do in the novel? What do they want? Everything____ is about a character can help us to understand him, from his____ (appear) to the kind of food he eats.

        Besides, the order ofthe story and the plot are ____(equal) important. Make sure that as you read, you make ____quick note of what happens in each chapter. This will help you bring the things you have noticed about thecharacter, setting, language andso on together. It's also an enormous help for you to retell the story after you have read it.

        Next, themes. They are ideas that a novel explores. ____ is a must to get the hang of the theme if you want to fully appreciate the novel. Perhaps loveis a major theme, or justice，or  ____(survive).

        Furthermore, novels are made up ____language. Writers use language in a special way____(make) their novels work. They may use metaphors, invent symbols, or show different characters' personalities through their speech styles.

$\frac{4}{7}$ ÷ $\frac{7}{4}$ ＝____ $\frac{1}{3}$ ×3＝____6× $\frac{1}{12}$ ＝____ $\frac{1}{7}$ ＋ $\frac{6}{7}$ ×7＝____

100÷10%＝____ $\frac{5}{9}$ ÷1＝____ $\frac{3}{7}$ ÷7＝____  $\frac{1}{3}$ ×9× $\frac{2}{3}$ ＝____