e used as 被用来当做作...be used to 被用来作....be used for 为了什么被使用.be used to doing.习惯于做...used to do 过去常常做某事（现在不做了）
He used to be a teacher,but now he is businssman
The locks are used for locking the doors
Japanese is used as the second foreign language in many universities in China
People are used to surfing the Internet now
Wood can be used to make pape