使用被動語態應注意：
1、不及物動詞無被動語態。
What will happen in 100 years.
The dinosaurs disappeared about 65 million years ago.
2、有些動詞用主動形式表示被動意義。
This pen writes well.
This new book sells well.
3、感官動詞或使役動詞使用省略to的動詞不定式，主動語態中不帶to ，但變為被動語態時，須加上to 。
例：make somebody do something→somebody+ be +made to do something
see somebody do something→somebody +be +seen to do something
A girl saw my wallet drop when she passed by.→My wallet was seen to drop by a girl when she passed by.
The boss made the little boy do heavy work.→The little boy was made to do heavy work by the boss.
