Born in a remote village ________ by endless mountains in Yunnan, I always dream of ________ the outside world.
You can only be sure of _____ you have at present; you cannot be sure of something _____ you might get in the future.
The traditional view is _____ we sleep because our brain is “programmed” to make us do so.
We arranged to meet at the cinema at 7:30, but he failed to ______.
Miss Green contributed fifty dollars, but she wished she could contribute _____.
When _____ different cultures, we often pay attention only to the differences without noticing the similarities.