关于英语换句It is impossible that a child can lift such a heavy bo

关于英语换句
It is impossible that a child can lift such a heavy box.
It is impossible _ _ _ _ _such a heavy box.
It hapened that you bad known each other other before.
You happened _ _ _ each other before.
It happened that yu bad known each other before.
这句话你能帮我翻译一下吗？
关于hope这个词，有hope for,hope that,还有那些用法？