Mary, stop to have a rest. You _________ the flowers in your garden for nearly two hours.

A．are watering

B．were watering

C．water

D．have been watering

下列不属于非离子型表面活性剂的是（）

A.司盘类

B.吐温类

C.卖泽类

D.苄泽类

E.硫酸化物