肥料三要素
参考答案：
植物对氮、磷、钾的需要量比较大，但土壤中含量又比较少，常常需要通过施肥来满足植物的需要，因此，常把氮、磷、钾叫做肥料三要素。
句型转换。
1. We have a basketball game. (改为一般疑问句)
______ ______ ______ a basketball game?
2. The school trip is October 30th. (对划线部分提问)
______ ______ the school trip?
3. My uncle is thirty. (同上)
______ ______ is your uncle?
4. Mary, are you thirteen years old? (作否定回答)
______, ______ ______.
5. What's your age? (同义句)
______ ______ are you?
去除蔬菜中有机磷类农药最好的方法是：（）
A.沸水浸泡
B.充分漂洗
C.碱水冲洗
D.太阳照射
