能够降低混凝土水泥用量的集料性质是（）。
A．集料的总比表面积较大
B．较高的空隙率
C．采用连续级配
D．采用间断级配
参考答案：D
This is the best hour I can _______ I_______ in the past twelve years. [ ]
A. know; have had
B. remember; had
C. think of; have had
D. think out; had
伤寒病人解除隔离的主要标准是（）。
A.体温下降
B.血培养转为阴性
C.体征消失
D.肥达反应阴转
E.症状消失，大便培养连续2次阴性（间隔5日）
