3÷(3-3)
=33-3
=13-1
=3+12．
故答案为：3+12．
_______ cooking, writing and running the farm, she was very busy.
A．Among
B．Between
C．Over
D．As
Wigand术式程序的第一步是（）
A.切除钩突
B.开放筛泡
C.切除中鼻甲基板
D.切除中鼻甲后部
E.开放蝶窦
