The students are very busy. Some are cleaning the room.        are watering the flowers.

— I hear your pen friend is visiting Suzhou at present. Is it the ______ time for her? — Yes, and she will come for a fourth time next summer.

--Must I finish my homework now, Mum?　　----No, you_____.

My grandpa often told _____ interesting stories. 

  ----There are sixty students in our class, and _________of us are boys.----Wow! You have forty girls.