It was along the Mississippi River _____Mark Twain spent much of his childhood. [ ]

Could you tell me the way ______ the railway station— Go along this road and soon you’ll find it.

With some books ________， he went into the bookstore on the way home

His wife is in bad condition now and he has to_____ a smiling face though heavy-hearted in the company.[ ]

________we went to visit Professor Smith,he________his research work.