隔离式自救器防护的是（）有害气体。
A.CO
B.CH4
C.所有
参考答案：C
It is the first time that I _____ in public.
A. have spoken B will speak C. had spoken D. will be speaking
在Oracle工具中，用于支持数据仓库应用的是
A．Oracle Discoverer/2000
B．Oracle Designer/2000
C．Oracle Developer/2000
D．Oracle Financials
