1.只有 be convenient to sb.这种用法,没有其他的
2.It's .(adj.) for sb.to do sth.对某人而言做某事是...的
3.There is no doubt that和 It is no doubt that都可以,都有这样的用法,只是比较常用There is no doubt that
there is no wonder that 和it is no wonder that 是一样的,广义上来说都有这样的用法,只是比较常用it is no wonder that