The pressure ______ causes Americans to be energetic, but it does put them under a constant emotional strain.
When I got to the cinema, the film _____ for five minutes.
Mary had promised to give me a ticket for tomorrow. She failed, ____.
—He must be busy doing his homework right now. —I imagine____.
Lu Xun was ___________ medical student before he turned ___________ great writer.
The mother often tells her son to be a good boy, warning him to______ trouble.