金属与石材幕墙构件应按同一种类构件的5%进行抽样检查，且每种构件不得少于（）件。
A．5
B．4
C．3
D．2
参考答案：A
On average, 50 percent of those _____ said they would prefer to see Mr. Obama win the 2012 ticket, _____to just nine percent who prefer Mr. Romney.
A．to be questioned; compared
B．having questioned; comparing
C．questioned; compared
D．questioning; comparing
组合逻辑电路的基本单元是（）。
