--How about going to school by boat, Lilei? --Good idea. That must be ___________than taking a bus.
—Must we finish the project in a month? —No, you _______.
—Which is _______, the sun, the moon or the earth? —Of course the sun.
—How many students are there in your school? —_______ students, I think.
—Would you mind my smoking here? —_______ It’s not allowed here.
—_______ do you have a sports meet at your school? —Once a year.