Waste water ____________________into Xiang River.It’s our duty to keep it clean.A. shouldn’t be poured B. mustn’t pour C. can’t pour
.----Why do you make friends with Joe ?---He isn’t a good student, but ________ he is friendly.
He must _____ his sister with her math.
The baby is sleeping. Please speak ________.
---I’m going for a summer camp in Beijing next month.--- ________.
--- Hmmm. I think I’m going to Shanghai.