普通混凝土常用的搅拌机型式为（），对干硬性混凝土宜采用（）。
参考答案：自落式搅拌机，强制式搅拌机
—Hi, Mr. Smith. Which department do you work in?
—I am in the Marketing Department now, but I ________ in the Sales Department before long.
A．worked
B．will work
C．have worked
D．will have worked
产褥期是指产后（）
A.2周
B.4周
C.6周
D.8周
E.12周
