建设工程项目质量控制系统运行机制的核心在于它的______。
A．动力机制
B．约束机制
C．反馈机制
D．持续改进机制
参考答案：A
球形支座按其水平位移特性分类为______
A．单向活动支座
B．双向活动支座
C．三向活动支座
D．固定支座
—____ last Sunday?
—I did nothing, and just stayed at home. [ ]
A. What did you do
B. Where did you go
C. Did you stay at home
D. Why did you do
