根据短文内容，选择最佳答案。

A

    Do you like blueberries? But maybe you don't know blueberries well.

    Farmers often grow them on bushes(灌木丛) in the field. A blueberry is small and round. Many blueberries can grow on one bush. At first, the blueberries are green. You can't eat the green berries. A lot of sun and rain help them become sweet. When the berries become blue and big, they are ripe and sweet.

    After the blueberries are ripe, people put them into boxes and bring them to stores and supermarkets. People buy the blueberries and take them home to eat. After they wash the berries, they eat them one by one. Some people like to cook with blueberries. They make blueberry muffins(松饼) and pancakes. They like to make blueberry juice. Others like to make blueberry ice cream. It is very cool!

如图，菱形ABCD，∠B=120°，P、Q分别是AD、AC的中点，如果PQ=3，那么菱形ABCD的面积为（　　）

课外阅读课上．老师将一批书分给各小组．若每小组8本．则还剩余3本：若每小组9本．则还缺2本．问有几个小组．（根据题意设未知数，只列出方程即可）