_______ the smoke come out of the building, my first thought was to call the fire department as soon as possible. 

He felt       to work for human rights and progress.

________ seems to be a strong competition　in China for senior high students to enter college or university.

-Thank you very much.　-You are welcome. I was _____ glad to help.

Depression is the leading cause of suicide, __    __ in turn is the third leading cause of death among 15 to 24 year olds in the United States．