manual signalling造句

例句与造句

1. These proposals failed, with the Upfield line instead receiving a series of upgrades to replace labour-intensive manual signalling systems.
2. The outer end of the token based systems and two-position manual signalling, where access to the line is based upon possession of a token.
3. It's difficult to find manual signalling in a sentence. 用manual signalling造句挺难的