在硫化氢浓度达到()时,工作人员必须立即佩戴适当的空气呼吸保护设备。
A.30ppm
B.20ppm
C.30mg/m3
D.50ppm
参考答案:B, C
财务会计报告分为()。
A.年度财务会计报告
B.季度财务会计报告
C.半年度财务会计报告
D.月度财务会计报告
In the 1990's,many well-educated young people went to Hainan Island ____ their jobs. [ ]
A. in favour of
B. in memory of
C. in honor of
D. in search of