It was on this vast grassland in Tibet________we saw those beautiful and magic Tibetan antelopes in2008 . [ ]

What’s in the fridge(冰箱) —______ some milk in it.

There is a big tree in ________ front of our classroom and a big blackboard_in ________front of it.

15.—Will you go to the party tomorrow， Xiao Hai？ —No, ____ I was invited to

Most supermarkets in Shanghai have stopped free plastic bags in the past few years.