He lives in the building roof is red.A. whose B. that C. which
—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.
The old man was _______ sad _______ say a word when he heard the bad news.
—Do you often help your cousin with his English? —No. He learns English _______.