About 60 percent of the students ________ from the south; the rest of them ________ from the north and foreign countries.
I never forget the day _____ we worked together and the day ____ we spent together. A when, which B which, when C what, that D on which; when
------ What do you think of the English dictionary? ------Not bad. You can’t find ______ in the bookstore.
It was a time_______ the killer whales helped the whalers catch the baleen whales.
Ladies and gentlemen, please remain ______ until the plane has come to a complete stop.
_______ a certain doubt among the people as to the practical value of the project.