—Tim, where is your sister?—She ______ sports on the playground.A. is doing B. does C. was doing
—What are those? —are their books.
—Is this _____ schoolbag? —No. It's _____.
Not only oral English but also written English _____ important.
—We’ll make a trip to Hainan Island next weekend. Will you go with us? —No, I can’t _____ it at present.
—How many students are there in the classroom? —_____ I don’t know where they have gone.