[观察例句]
写出下列句中动词ing的作用
①Walking in the park，she saw an old friend. 时间状语
②Being ill，he couldn't go to school.原因状语
③Working hard，you'll make great progress.条件状语
④The boy ran even faster，reaching the school out of breath.结果状语
⑤All night long he long awake，thinking of the problem.伴随状语
⑥Is there a swimming pool in your school？前置定语
⑦The bridge being built now will be the longest one in the world.后置定语
⑧He heard the song being sung next door.宾语补足语
