It is very kind ____ you to help me with my lessons. It is hard ____ me to learn them well.
---The classroom is not________ clean ______it was yesterday . ---Sorry, I forgot to clean it.
As(正如) the old ___________ goes, “Time waits for no man!”
The book isn’t _____________________. We don’t like it.
The Science Museum interests me a lot. I enjoy __________ there.
Zhao Peng likes to eat chocolates but he ________eats them before going to bed, because he thinks it’s not good for his teeth.