The Kowloon-Canton Railway started operation in 1910 and was double-tracked and electrified in the early 1980s.
九铁在一九一零年投入服务时是一个单轨系统，在一九八三年，已改善成为一个完全电气化的双轨铁路系统。
Admittedly, this property is a confusing one because it reads like a double negative, but by default, all read and unread documents are tracked in a database.
大家都认为这条属性令人费解，因为它读起来像是一个双重否定句，但是在默认情况下，数据库中所有已读的和未读的文档都会被跟踪。
Freddie's voice is double tracked and at the top of his range.
Freddie的声音在制作上运用了立体声录音（double tracked），且达到了他的最高音域。
Freddie's voice is double tracked and at the top of his range.
Freddie的声音在制作上运用了立体声录音（double tracked），且达到了他的最高音域。
应用推荐