种牛痘疫苗可以控制住天花.Smallpox can be contained by vaccination.种牛痘可以免患天花.Vaccination immunizes people against smallpox.种牛痘防天花是有效的.Vaccination for smallpox is efficacious....
Buses and trains use much less fuel per person than cars.公共汽车和火车的人均燃料耗费量比轿车小得多。Freight trains travel slowly on upgrades into the hills.火车徐徐向山上驶去.Many trains have been cancelled and a limited service is operating on other...