直埋电缆沟底电缆上、下应铺设厚（）mm的沙或软土。
A.50
B.100
C.150
D.200
参考答案：B
----- I can’t find Mr Brown. Where did you meet him this morning?
------It was in the hotel _______ he stayed.
A．that
B．which
C．where
D．when http:/
甲公司向乙公司开具了一张金额为20万元的商业承兑汇票，乙公司将此汇票背书转让给丙，内又将汇票背书转让给甲。甲存汇票得不到付款时，可以向丙行使票据追索权。 ( )
