上 shàng -To go

上 is used to indicate someone is going somewhere or doing something. As a direction word 上 also means "on" or "on top of". 

Examples:

• 我要上课。 / 我要上課。 Wǒ yào shàngkè. -I am going to class.
• 我坐公共汽车上班。 / 我坐公共汽車上班。 Wǒ zuò gōnggòng qìchē shàngbān. -I take the bus to go to work.
• 书在桌子上。 / 書在桌子上。 Shū zài zhuōzi shàng. -The book is on the desk.