是begin to do sth还是begin doing sth?

是begin to do sth还是begin doing sth? begin to do sth.以及start to do sth.的现在完成时形式.begin to do sth.以及start to do sth.的现在完成时形式是have begun to do sth.和have started to do sth.还是用be on?注意,我说的是begin to do sth.这个词组,不是begin begin to do sth begin do sth begin dbegin to do sth begin do sth begin doing sth哪个有错 是be eager to 还是 eager to do sth 容易做某事 是easy to do sth 还是be easy to do sth 容易做某事 是easy to do sth 还是be easy to do sth begin to do sth 和 begin doing sth begin to do sth和 begin doing sth的区别 be worth to do sth 还是be worth doing sth be scared to do sth还是be scared doing sth be glad to do sth 还是be glad doing sth be heard to do sth 还是 be heard doing sth? 是be busy doing sth还是be busy to do sth? 请问是be pleased to do sth还是be pleased with sth 被使做某事 是 be made to do sth?还是be made doing sth? be busy加什么?be busy是接doing sth还是to do sth? have sth.to do和have sth.to be down和have sth.down是have sth.to do和have sth.to be down意思相同,还是have sth.to be down和have sth.down相同? 是begin to do还是begin doing 或是都可以?