—Listen! Is Mary singing in the next room?—No. It _______ be Mary.She has gone to Shanghai for an important meeting.
—What ______ you ______?—I _______ the dishes.
—What's Mary doing?—_______.
My friend pal and I often talk _______.
—Is your brother _______ TV?—No,he's _______ a book.
Listen,the girls ____ an English song.