题目

农作物生长需要含较多氮、磷、钾元素的化肥，下列化肥属于含磷复合肥料的是（    ） A.NH4NO3   B.Ca(H2PO4)2   C.(NH4)2HPO4   D.KNO3 答案：CThe windows _______ after school is overA.usually closeB.usually closedC.are usually closedD.are usually closing