抓现行英文

6. After autumn arrives, the city looks like an old man with leaves falling from the tress.从from the trees可知树叶正在从树上落下，用现在分词表示“进行"。7. The murderer was brought in, with his hands tied behind his back. 由于是murderer（杀人犯），手理应被捆绑在后面，过去分词表达被动和完成。8. With a lot of workto do, I can't go out. 由于有很多工作要做，我不能出去。动词不定式to do表示将来，将要做，如果用过去分词done,则表示已做完。9. The missing boy was last seen playing near the river.失踪的男孩最后一次被看到在河边玩。see sb. doing sth. 看见某人正在做某事, 变成被动语态后, 就成了: sb. be seen doing sth...10. I caught him picking flowers. 抓现行，他正在摘花。