当x=0.3时，4x=______，2x=______．
当x=0.3时，
4x=4×0.3=1.2；
2x=2×0.3=0.6．
故答案为：1.2，0.6．
—What's wrong with you?
— I feel _____. I heard a _____ noise just now. [ ]
A. frightening, frightened
B. frightening, frightening
C. frightened, frightening
D. frightened, frightened
鼓风机是生化池的关键设备之一，它的运行状态直接影响污水处理的质量，在启动前必须做哪些检查？
