It has always been the _____ of our firm to encourage workers to take part in social activities.
--May I open the window? It’s too hot. --_____________.
John began to study French last Sunday. ____________
Some plants are so difficult to grow that they can only ______ in a perfectly clean environment.
The family finally climbed to the top of the Mount Tai, ________.
Only after he was taken to the teachers’ office did he admit ______ the window.