.Seeing the happy _________of children playing in the park, I’m full of joy and confidence in the future of our country.
Why are you leaving right now? You promised to stay ____ hours.
We asked John and Jerry, but ____ of them could offer a satisfactory explanation.
This book______18 articles , _______ three written by my father.
Chest pains can be a warning ____of heart problems.
_______ is mentioned above, the number of the students in senior high school is increasing.