----- Have you heard of Earth Day ?----Yes . The first Earth Day ______ in 1970 to educate us to protect our planet .
I’ve lived in Maoming________1999. A.for B.by C.since
—________have you been married? —For twenty years.
They________a hit CD in the last six months.
They________to Tibet many times.
Most of the young people can hardly speak any Chinese,________?