Building that railway was very difficult and involved ___ ten tunnels.
举一反三
- "The railways are very important in _________________ building across Asian economies. Because it connects the Silk road economic belt and the maritime silk road," said Wang Gengjie, Chief Engineer of Kunming Railway Administration.
- The police are very reluctant____ involved in this sort of thing.
- his theory is very difficult
- He was going ____ a very difficult time.
- The building is functional. There is nothing very __________ (decorate) in it.