国际私法的渊源是指赋予国际私法规范以（）的法律文件的表现形式．
参考答案：法律效力
简述凝血因子ⅩⅢ定性试验的原理。
-- Is it easy from my building to yours?
-- Yes. And we look forward to you at the party.
A．to walk; seeing
B．to walk; to see
C．walking ; to see
D．walking ; seeing
