–You speak very good Chinese. --Thanks. I _______ it for 4 years before I came to China.
.It _____we had stayed together for a couple of weeks ____I found we had a lot in common.
.In my opinion, life in the twenty-first century is much easier than _______.
.He said he _________ experiments those days.
There was a heavy curtain ________ the light.
. These old buildings possibly __________ the Ming Dynasty.