Be careful when you take exams. Check your paper to ________ there are no mistakes before you hand it in.
Helen caught a cold the day before yesterday. But she’s ______ today.
—How many students are there in your school? —About_______ students, I think.
Tom is ______ of the six boys.
——Must I take the medicine every day?—No, you _______.
—I looked for you in the office, but I could’t find you. —Oh, I in the library