网址：http://m.1010jiajiao.com/timu_id_1376334[举报]
—Who is the best friend of ______ at school?
—I think Helen is． We often help each other．
A． mine B． his C． yours D． hers
－Who is the best friend of ________ at school?
－I think Helen is．We often help each other．
A．mine
B．his
C．yours
D．hers