The police officers in our city work hard __________ the rest of us can live a safe life.
After months of voyage, Columbus arrived in_____ later proved a new continent.
The door opened and in _____.
According to the Ministry of Health, by May 1, 2003, the total SARS deaths on the Chinese mainland_____to 170.
---Tom, keep your_____ on your studies. --- Sure, mum. I'll keep that in_____.
You don't have to share the umbrellas. I'll give you one_____.