I posted a book to her three weeks ago. She________have received it.
I think that's unlikely to happen, but if that_______, both America's and China's interest would be severely damaged.
One _____ of being able to speak English is that you will have more job opportunities.
---He lost his job last week, but he seems happy.---I think he _____ to put on a brave face.
The sick salesman was happy to stay at home because doing _____ was a thorough rest for him.
Sorry, sir, but you can’t go any further without______boarding pass. Please obey ____ rule.