–-Do you know about Han Han? --Yes, he ______ a playful student when he was in secondary school, but now he is one of the most popular writers in China.
_______he is busy, ________he helps us often.
Your child is only five. Is _____necessary for you to be so strict with him?
My mother always has__________ housework to do on weekends.
It’s important ______us to learn English well.
Liu Lei is ________better at Chinese than Liu Ying.