Tyger精囊：一词多义，先结构再翻译，千万别死记。
学员问：before又是介词，又是连词，还是副词，含义都差不多，怎么区分？
Tyger答：结构区分
连词：Work on it had begun before my sister left.
副词：My brother has never been abroad before.
介词：I got up before dawn.
学员问：write既是及物动词又是不及物动词，含义都差不多，怎么区分？
Tyger答：结构区分
不及物：Both girls write to each other regularly now.
及物：I spent the whole day in my room, but I did not write a single card!
学员问：outside既是副词，又是名词，还是形容词，最后还能是介词，含义都差不多，怎么区分？
Tyger答：结构区分
介词：I found this outside this gentleman's room.
副词：It was dark outside.
名词：As soon as he opens the gate from the outside, he comes into the garden and waits until the gate shuts.
形容词：the outside air
