Susan is my good friend and she always helps me _______ my Maths.
Doctor Wang operated _______my mother yesterday.
— Where is your boss? I haven’t seen him for several days. — He ____ to Shanghai on business.
It was raining heavily, _____ we decided to stay at home and watch TV.
Dr Bethune came to China ______the Chinese soldiers and gave his life to ____Chinese.
I asked Jim and Bob to come to my house for dinner , but ____ of them came .