()是把污浊空气从室内排出,将符合卫生要求的新鲜空气送进来,以保持适于人们生产及生活的空气环境。
A.空凋
B.排风
C.送风
D.通风
参考答案:D
As soon as I got on the bus I realized that I________ my papers in the house.
A.left
B.was leaving
C.had left
D.have left
复合判断就是自身中______的判断。