He paid for a seat, when he________have entered free.
In their spare time, they will discuss the _____ to the study of English.
About _____ of the population of that country _____ on farms.
―Will you go to the Great Wall with us?―If John wants to go, _______
I was so angry that I felt like _________ something at him.
The famous scientist grew up _______ he was born and in 1950 he came to Nanjing .