Mr. Smith is always on time for everything. How ________ it be that he was late for the flight?
Our teachers do believe that all the students in our school will do well in the coming college entrance examination, _______?
—So when did you meet Joan?—It was last Sunday _______ she came to visit my sister.
—What do you think of Mrs. Smith? —She is _______ of a good housewife, for her children’s room is always a terrible mess.
—Would you like to join us in the barbecue this Friday afternoon?—Sorry, _______.
The charity sale our school organizes every year has taught us much. _______ we would never have learned it in class.