l saw Ben______football in the playground just now. (play)
问题描述：
l saw Ben______football in the playground just now. (play)
答
是playing
see有两个结构
see sb.do是表示看到全过程
see sb.doing 是看到某人正在做某事
根据句意 我不可能从Ben开始踢足球就看他 而是碰巧看到了他正在做这件事.
用 playing