设计合同规定，办理各设计阶段设计文件的审批工作应由( )负责。
A．设计单位B．业主C．承包人D．监理人
参考答案：B
43. Learning a foreign language well takes a long time, ________?
A．doesn't this
B．does this
C．doesn't it
D．does it
电气防火、防爆的措施有哪些？
