We will never forget the factory _______ we worked last year.
Though tigers are ______ to people, they are ______ now and we should protect them or they will die out.
Some passengers were ______ in the traffic accident and taken to the nearest hospital.
It was along the Mississippi River _____ Mark Twain spent much of his childhood.
The house they are living now is ______ our house.
Milu deer,which used to be ______ in China long ago,is a rare animal nowadays.