--_________is the population of the world ? --_________about 7 billion.A. How many; It’s B. What; It’s C. What; They’re
—Who usually ________in your family ? —My mother does .
It’s ten o’clock. Betty _______ piano.
They are always ready _______ helping.
Mary isn’t ________ a book. She is ________ TV.
Who are you talking _________?