The teacher came into the classroom with a book ___ his hand.A on B in C at D of

问题描述:

The teacher came into the classroom with a book ___ his hand.A on B in C at D of
应该选哪个?为什么?

选 in
eg:Tom went swinging down / along the road with a book in his hand.
汤姆手里拿着一本书,在路上轻松地走着.