用所给词的适当形式填空:We have a friend ----- (call) sanday

用所给词的适当形式填空:We have a friend _____ (call) sanday
用所给词的适当形式填空:
We have a friend _____ (call) sanday.
It's not easy _____ (study) English well.
I enjoy _____ (listen) to music before going to bed in the afternoon.