* * 的血液供应主要有（）.
A、胸廓内动脉
B、胸外侧动脉
C、肋间动脉穿支
参考答案：A, B, C
I didn't know _____ yesterday.[ ]
A. why isn't Danny in school
B. why wasn't Danny in school
C. why Danny isn't in school
D. why Danny wasn't in school
在平均收帐期一定的情况下，营业周期的长短主要取决于（）。
A.存货周转天数
B.流动资产周转天数
C.固定资产周转天数
D.生产周期
