刮板机按传动方式分为（）和液压传动刮板输送机。
A、电动传动
B、电力传动
C、单速电动机
D、双速电功机
参考答案：B
Ten years ago the population of our village was _________ that of theirs.
A．as twice large as
B．twice as large as
C．large as twice as
D．as twice as large
为了使工程项目参建各方依法履行各自的责任和义务，在工程建设中必须实行( )。
A．合同管理制
B．建没工程监理制
C．工程招标投标制
D．项目法人责任制
