建设工程项目质量控制系统运行机制的核心是它的______。
A．动力机制
B．约束机制
C．反馈机制
D．竞争机制
参考答案：A
He accidentally _______ that he had quarreled with his wife and that he hadn’t been home for a couple of weeks.
A．let out
B．took care
C．made sure
D．made out
使“秀才不出门，便知天下事”的说法变成现实是通过 [ ]
A．激光技术
B．航天技术
C．计算机网络技术
D．生物工程技术
