你是从哪里来的？Nǐ shì cóng nǎlǐ lái de?
从 cóng (from)
你们从几点到几点上课？Nǐmen cóng jǐ diǎn dào jǐ diǎn shàngkè?
上课 shàng kè have class，从 cóng from
从俄罗斯到捷克坐飞机要多长时间？ Cóng Éluósī dào Jiékè zuò fēijī yào duō cháng shíjiān?
从 cóng from，要 yào need / will take，到 dào to / until