__________ on Wechat is a common phenomenon, and more people hardly write letters.
I’ve lived in New York and Chicago, but don’t like ____ of them very much.
There are a small number of people involved, possibly ______twenty.
(2013·浙江,11)Half of ________ surveyed in 16 countries say they go first to their closest friend to share their deepest wishes and darkest fears.
Recycling is one way to protect the environment; reusing is ________.
The project requires close teamwork. ________ will be achieved unless we work well together.