23.Since she ______ (miss) the last train,she had to walk home.24.______ (miss) the last train,she had to walk home.25.They stood on the playground,and ______ (watch) a football match.26.They stood on the playground,______ (watch) a football match.

23.Since she ______ (miss) the last train,she had to walk home.24.______ (miss) the last train,she had to walk home.25.They stood on the playground,and ______ (watch) a football match.26.They stood on the playground,______ (watch) a football match.
23.Since she ______ (miss) the last train,she had to walk home.
24.______ (miss) the last train,she had to walk home.
25.They stood on the playground,and ______ (watch) a football match.
26.They stood on the playground,______ (watch) a football match.

23.Since she ______ (miss) the last train,she had to walk home.24.______ (miss) the last train,she had to walk home.25.They stood on the playground,and ______ (watch) a football match.26.They stood on the playground,______ (watch) a football match.
had missed
Having missed
watched
watching

23. Since she __had missed/missed____ (miss) the last train, she had to walk home.
24. _Having missed/ Missing____ (miss) the last train, she had to walk home.
25. They stood on the playground, and _watched_____ (watch) a football match.
26. They stood on the playground, _watching_____ (watch) a football match.

23.miss miss的过去式就是miss......
24.Missing 动词短语作主语，动词应该加ing变名词形式
25.watched 这个没什么好说的吧，一个普通的句子
26.watching 表两个动作并列的一种结构，后面那个加ing