人的鼻孔呼吸是左右轮换，每隔几小时交接一回班？（）
A.2小时
B.4小时
C.6小时
参考答案：A
The government said that a military exercise would be held on Monday off the country's central
coast, and it warned other ships to ________ the area. [ ]
A．surround
B．avoid
C．enter
D．observe
根据《建筑业企业资质管理规定》，建筑业企业资质中施工总承包序列企业资质设（）。
A.特级
B.一级
C.二级
D.三级
E.四级
