一般时 to doto be done
进行时 to bedoing
完成时 tohave done to have been done
完成进行时 tohave been doing
To speakgood English is not easy.
or： It is not easy to speak good English.
(采用形式主语 it 以避免头重脚轻)
It took mean hour to do the work.
Shedecided to take the examination.
I hope tomeet him soon.
They expectedus to help them.
He wantshis son to study hard.
不定式作宾补，如谓语动词是感官动词，使役性动词(see， hear， notice， watch， make， have， let...)，则不定式符号“to”须省略，但在被动语态中不能省。
I heardthem sing in the classroom.
I made herclean the room.
The girlis heard to sing an English song.
To teachis to learn.
His job isto sell cars.
We come toschool to study English.(目的)
= in orderto
I hurriedto the store， only to find it closed.(结果)
He askedfor a piece of paper to write it on.
= to writeit on the piece of paper.
The poorman has no house to live in.
= to livein the house.
Have youanything to do？
= to doanything
She seemsto dance very well.(现在情况)
She seemsto be dancing in the dancing hall.(正在进行)
She seemsto have danced well.(过去情况)
Has washappy to have been staying with his uncle.(动作持续一段时间)