己知7a=8b，那么a：b=______：______．
因为7a=8b，
则a：b=8：7；
故答案为：8、7．
钝性分离适用于______。
A．皮肤 B．肌肉 C．胃D．肠 E．子宫
My cousin David was born _______ 2000, _______ a winter afternoon _______ December.
A．in; on; in
B．in; in; in
C．in; in; of
D．in; on; of
