外源性凝血途径的常用筛选试验是()
A．凝血时间测定
B．APTT测定
C．血浆凝血酶原时间测定
D．凝血酶原消耗试验
E．复钙时间测定
参考答案：C
He did his best to make them what he meant, but it didn’t help.
A. understood B. understand C. to understand
