But steamships didn't lose their sails until the 1880s, because early marine engines had a nasty habit of breaking down. Until ships became large enough (and engines small enough) to mount two engines side by side, they needed to keep sails. (CET4-2014.6)
举一反三
- Sails are still valuable until the ship becomes large enough to install two engines next to each other. A: A B: B C: C D: D E: E F: F G: G H: H I: I J: J K: K L: L M: M
- New cars are becoming faster and faster because ______. A: the efficiency of the engines has improved a lot B: the engines are more powerful C: people like driving fast D: highways provide enough chances for fast driving
- In large marine diesel engines cylinder oils usually contain additives formulated to impart the （） to clean the rings and grooves.
- Large marine diesel engines of crosshead construction generally have two systems of lubrication: a total loss system feeding the （） and a recirculation system lubricating the running gear and cooling the piston.
- Which of the following will be the function of lubricating oil used in marine engines?（）