马汉出于改善美国地理位置沟通两洋交通考虑，建议美国政府开挖（）运河并控制运河区。
A.苏伊士
B.基尔
C.巴拿马
D.克拉
参考答案：C
—I'm very sorry I didn't call you last night.
—____ I guess you were busy. [ ]
A. I'm sorry, too.
B. It's nothing.
C. You are so nice.
D. Excuse me.
使纤维蛋白分解成纤维蛋白降解产物的因素是
A．凝血酶
B．蛋白C系统
C．因子Ⅵ
D．纤溶酶
