___ by thick bamboo and high forest, the ancient city hadn’t been discovered until the 1990s.
Although the first part is easy, the rest ______.
Mary’s mother got sick, so she called ______.
This project _____ considered thoroughly, and I’m sure it _____ finished on time.
When he got off the bus, he found his pocket ______.
------ Look, where are you going ? ------ Oh, I’m terribly sorry. ______.