— Peter , I won’t visit our teacher this Sunday .— I have to look after my mother .
---How many students have visited the West Lake? ---________.
When I was in the USA,I had difficulty ______ English, so I often ask Paul ____ help.
The river is too wide for the swimmers _______________.
I don’t know ______ with this problem. It’s too hard.
The notebook ___________ be John's .There is his name on it.