GPS的每条卫星轨道上有( )卫星。A.3颗 B.4颗 C.5颗 D.6颗 发布时间:2018-06-29 09:30 │ 来源:www.tikuol.com 题型:单项选择题 问题: GPS的每条卫星轨道上有( )卫星。A.3颗B.4颗C.5颗D.6颗
题型:单项选择题 Halloween is believed to be a day ______all the spirits come back to the world of the living, and we have the same day in China called “Guijie", the Day of Dead.A.whereB.whenC.whichD.that 查看答案
题型:单项选择题 汽油机是工农业生产中常用的热机.若某汽油机的效率是20%,飞轮转速是1200r/min,汽油的热值是4.6×107J/Kg,则在汽油机内完全燃烧2Kg的汽油能放热______J,这些热通过该汽油机转化的能对外做有用功为______J,该汽油机每秒钟内完成______个冲程,做功______次. 查看答案