降温持续时间根据病情决定，一般需__________天，严重者可能要________周以上。
参考答案：2～3；1
With so many friends _____ me, I had no difficulty finishing the work on time. [ ]
A. to help
B. helped
C. helping
D. have helped
动力环境集中监控系统的3级结构中（）属于管理层。
A、SC，SU
B、SC，SS
C、SS，SU
