We all want to try something new, but finding the _________ to start is always the hardest part.

A．success

B．pride

C．courage

D．progress

激活凝血因子X的内源性激活途径一般开始于

A．损伤组织释放因子Ⅲ
B．血小板聚集
C．接触激活因子
D．磷脂胶粒表面阶段