--Where is Xiao Wang?--I don't know. He__________ be in the library.
Last month I was lucky enough to have a chance to make a trip into _____ space with my friend Li Yan ping, _____ astronomer.
Our class ______ forty-five students, in other words, forty-five students ______ our class.
The rare animals would die _______ if men were allowed to shoot as many as they wished.
The prize will go to the writer ________ story shows the most imagination.
The reason _______ he was absent from the meeting is_____ he suffered from a headache.