继续高二英语疑问1.-Which one do you like(better)of the two?-The smal

继续高二英语疑问
1.-Which one do you like(better)of the two?
-The smaller one.
有这么个句型,the+adj./adv.+of the two"两个中更...的那一个"
这里怎么讲?
2.They were walking( )the building when they ( )their teacher.
A.across,were seeing B.through ,met C.along,had seen D.around,had met
为什么选B/
3.Do you think that John will be (on )the team?
A.in B.on C.for D.at
为什么不能选D?