1. 動詞不定式的將來式

主動：be to do

被動：be to be done

表示預計要發生或按計劃要發生的事情

China is to be one of the most important contries in the world.

被動式與過去分詞的區別

the surfaces to be glued

the surfaces glued

2. 動詞不定式的完成時

主動　　to have done

被動　　to have been done

表示不定式的動作發生在謂語之前

I’m glad to have seen your son yesterday.

3. 某些adj. 后主動表被動

This plas is difficult to come out
easy

hard