有一个英语词组be hard to do,不是说一个句子只允许出现一个动词吗?那这句为什么有两个动词?be和hard如题!~

有一个英语词组be hard to do,不是说一个句子只允许出现一个动词吗?那这句为什么有两个动词?be和hard如题!~ 确定做某事的英语词组be sure to do等不等于be certain to do?又没有一个词组是be certain to do 求英语词组辨析be to do,be going to do ,be about to do三者都有表“将来”的意思,具体有什么区别呢?请举例说明, 请英语好的帮忙用几个单词造句有10个单词（词组）mad,anymore,direct,reported speech,first of all,message,pass on,suppose,be supposed to,hard-woking,do well in 有be hard to do sth的结构吗? 请问有be difficult to do sth 这个词组吗?be difficult XXXXX 还有什么词组? 这几个词组有什么不同?(英语)(1) be used to do sth.(2) be used to doing sth.(3) used to do sth. 乐意做某事英语词组是什么是不是be willing to do,还是be willing to doing be surprised to do同义词组 词组 sb be said to do 急求：初二水平英语造句用be mad at be supposed to do well in happen borrow pass用这些词组各造一个句子 是be surprisde to do 还是be surprising to do?（词组）词组咋写 有没有want sth.to do这个词组?怎么用?以及want sth.to be done? 用be trying to do sth 英语词组造句大虾们,教教我吧55555555555555555555555555555555555555555555555 一个很简单的英语问题!急!be going to do ,be going to be ,will do,will be有什么区别?详细一点,谢谢各位了 送分拉!最容易的14道英语题.很容易的,使用下列词组的正确形式填空.can't wait to be supposed to do with be gone go out not...any more deserve to instead ofbe hard on now that be rude to feel like in chargego unpunished1.Since I 常用句型it can be hard to do...和it is hard to do 有何区别?两个都是啥意思?在意思上是否一样?it can hard 行么?为何家be hard是啥词性? 英语一些短语词组的用法区别：need+v-ing和+to do的区别,be supposed to do还是be supposed to be doing?