英语中已动词开头的词语,什么时候用do?什么时候用to do?什么时候加ing?

有些动词后面只接不定式,也就是to do
如 hope,wish,help,decide,ask,learn,teach,choose,agree,plan,encourage,tell,use,invite,send,fail,refuse,offer,afford,preptend,promise,以及词组would like,get/be ready,do/try one’s best,make up one’s mind等.注：help后接不定式时,to可有可无.
例如
hope to do
wish to do
would like to do
有些动词后面只接动名词,也就是接ing
enjoy,finish,practise,keep,mind,spend,miss,imagine,be busy,have fun,have problems,feel like,give up,can’t help,be worth,look forward to,pay attention to等.
例如：enjoy doing
miss doing
can't help doing