doing 和 be doing 哪个算非谓语?非谓语都包括哪些形式呢?

doing 和 be doing 哪个算非谓语?非谓语都包括哪些形式呢? be doing和doing的用法区别 to be doing 和 doing的区别 be+doing be busy doing 和 be busy in doing 的区别? 用 be doing 和be doing to do 造句 三个 be fun doing 和have fun doing的区别 there be doing 和there be to do哪个是表示经常性的? be+adj.+doing sth和be+adj.+to do sth哪个队 get used to 和be used to 哪个加doing 哪个加动词原形啊! 将来时有BE DOING么?be going to do和BE DOING是算在现在进行时表将来? 存在have been doing、have being doing、和have be doing吗? 各举一个be+doing+while+be+doing和be+doing+when+did的例句,be最好为过去时 be up to do 还是 be up doing 哪个对 be used to doing 和 used to do 这两个短语哪个用于延续性 可不可以用be doing,when be doing? be used to doing used to doing?be used to doing used to doing?这两个词哪个正确?如果都正确那么他们有什么区别? be said to be doing和be said to have been doing的区别