eg:The girl came to the classroom , singing and dancing.
形式一注意：',' 后有only , 非谓V形式为 to do/ to be done
形式二：主语（n）+非谓V+谓语V+宾语
eg: The girl siting under the tree is my sister.
形式三（独立主格）：n+__非谓V__ , 主语+谓语.（前后半句主语不一致）
eg: The flight having been canceled , we had to get there by train.
固定搭配
feel sb do 一感:feel 二听：listen to ,hear 三让：make , let , have 五看：see, watch , look at , notice , observe 半帮助：help sb to do,help sb do 注意：make sb do = sb be made to do
1.It is useless/ no use/ no good +doing：多指一次性具体行为，译为做某事是没用的； 2. It is no use to do :多指习惯性行为，译为做某事没用。
afford to do sth:负担得起做某事； agree to do sth:同意做某事
Not+非谓V ，非谓语的否定用法
eg:Not having received a reply , he decided to write again.
