例句與造句

1. Initially, train dispatchers issued train orders using American Morse code over telegraph wires.
2. The ability for a single dispatcher to issue train orders was enabled by the invention of the electric telegraph in the 1840s.
3. Later, after the telephone was invented in 1876 and became common, most railroads constructed their own telephone systems, for internal communications, which the train dispatchers used to issue train orders.
4. It's difficult to find issue train order in a sentence. 用issue train order造句挺難的