The trains will travel at either 300km or 250km an hour.是什么意思?

The trains will travel at either 300km or 250km an hour.是什么意思? this will relieve pressure on the trains to some extent.这里为什么用on,是什么用法 this will relieve pressure on the trains to some extent.这里为什么用on,是什么用法 Trains as hard as you can__you will win the race.a.butb.orc.andd.then选哪个?为什么? 情态动词能不能做谓语This will relieve pressure on the trains to some extent.will是不是作谓语还有这句话的句子结构和成分是什么. 这个句子是虚拟语气吗?If operated by computers in the future,many trains will have no drivers.如果是的话为什么不符合一般虚拟语气的标准呢?为什么不是many trains would have drivers呢? What does the writer think of trains? There will be ______ for the first time in the near future in KunmingA.buses B.cars C.subways D.trains there will be ___ for the first time in the near future in kunming.A buses B cars Csubways D trains Trains moved slowly in the 1920s ,but they ___ move more quickly than in 1910A were to B did C will D can That's what he said,planes will take the place of trains.有这样的句子吗?怎么分析后半句与前半句的关系? Hello,I want to go to Hangzhou.Will you help me ___the times of the trains?A.look up B.pick up C.look for D.pick out This will relieve pressure on the trains to some extent.to some extent为什么用介词to,在某种程度上,是不是应该用on呢 There are some toy trains on the table.(对some toy trains 提问） most students take trains to school,中的take trains 能替换成take the train吗 文章：There are all kinds of trains in the world.There are trains to carry people,trains to carry animals and trains to carry things.There are fast trains and slow trains.Some trains go under the ground and some trains go through hills.In big citi this will relieve pressure on the trains to some extent .pressure前为什么不加the?on the trains是pressure的后置定语,为何pressure前不加the?是因为文章不着重强调pressure（压力）么?加the也可以吧?好像Mr.x who was resp 英语翻译A comprehensive Maintenance Plan for maintaining the service condition of the trains will be developed and submitted to the Client 6 months before Instruction to Proceed of the first train for Client’s review and confirmation.The Client