谁能告诉我used to do ,be used to do 和be used to doing的

谁能告诉我used to do ,be used to do 和be used to doing的

used to do 表示过去常常做某事，而现在往往不做了

i used to get up early in the morning when i was still a hight school student.

be used to doing 表示习惯于做某事

i am used to eating rice now.

be used to do表示...被用来做某事

Pig Stem Cells to Be Used to Grow Human Organs?

used to do 过去常常现在没做

过去常干 被用来做 习惯于干

这是三种时态，第一个是一般现在时，第二个是过去完成时，第三个是现在进行时。

区别大着勒