see sb do/doing sth 在什么情况下加to ?
如句子:Betty is often seen( B )the old man with his housework.
A.help B.to help C.helped D.helps
为什么要加to?请帮忙解释原因,谢谢
see sb do/doing sth 在什么情况下加to ?
如句子:Betty is often seen( B )the old man with his housework.
A.help B.to help C.helped D.helps
为什么要加to?请帮忙解释原因,谢谢
原型see sb to do sth 看见某人做了某事
倒装+被动+过去式:sb been seen to do sth 整句意思:贝蒂被看到帮助那个老人打扫房间
只有在被动的时候
句型是
sb. be seen to do