第1个回答 2012-09-25
We must talk to old people politely.
是对的,没问题
第2个回答 2012-09-25
We must ( speak) (to) old people ( politely)本回答被提问者采纳
第3个回答 2012-09-25
we must talk to old people politely
按语法来说 大家都没有问题
第4个回答 2012-09-25
We must talk with old people politely.
第5个回答 2012-09-25
we must (talk) (to) old people (politely).