小腿创伤后所致的慢性溃疡其主要原因为A．血运较差，愈合能力欠佳 B．静脉回流受阻 C

血液有哪些生理功能？

     Jack had a fever,       he finishing doing his homework yesterday.  

A．Although; but

B．But; although

C．Although; /

D．/;although

煤层根据厚度分为哪几类？

脱硫系统DCS的控制范围？

下面哪项业务属于群组业务：（）

A.家庭情亲网

B.IDC业务

C.安全厅V网

D.中央ADC