传送网包括()和传输网两部分。
A.同步网
B.智能网
C.接入网
D.管理网
参考答案:C
My sister ________ for long when she fell seriously ill.
A.didn’t marry
B.has been married
C.hadn’t been married
D.wasn’t married
在合同履行时,债务人提前履行给债权人增加的费用,由负担( )
A.债务人
B.债权人
C.受益人
D.二者共同负担