It is the interaction between people, rather than the events ___ occur in their lives, ____ is the main focus of social psychology.
You say he works hard, __________ and __________.
How long have you __________ the army?
He was filled with sadness as he watched her __________ the crowd.
She will ________ an important meeting next week.
I was told that there were about 50 foreign students __________ Chinese in the school, most __________ were from America.