vacant  指“未被占用的”尤指土地、房屋、座位、职位等空着，未被占用的，相似于   unoccupied。

    1）They have decided to buy a piece of vacant land in a view to building a new

       office block. 

       他们已经决定买一块空地建造一幢新的办公大楼。

    2) I'm looking for work; are there any vacant positions in your company?   

       我在找工作, 你们公司有空缺的职位吗?

    3）We had a lot of bother finding a vacant apartment near the universtiy.    

       我们费了不少周折才在大学附近找到一套空闲的公寓房间。

    4）Could you find out for me whether it has any vacant rooms for the day after

       tomorrow

       你能不能帮我查一查后天是否有空房间？

empty   普通用词，指某物中没有任何东西，也可指谈话等空洞没有内容，没有意义。

    如 empty talk、empty promise。

   1) Burglars broke into the empty flat while the tenants were away on holiday.

      窃贼在租户外出度假期间闯入空房偷走了东西。 

   2）Throw those empty bottles into the dustbin.   

      把那些空瓶子扔进垃圾箱。

   3）He turned his pocket inside out to show me that it was empty.  

      他把衣兜翻过来给我看里面是空的。

   4）No one believes a person who always makes empty promises.    

      没有人会相信一个总是开空头支票的人。

   5）Nothing can possibly come out of all this empty talk.   

      这样空谈一通是不可能有什么结果的。

hollow  指“空心”，指物体内部或中心是空的或有洞的或指“凹陷”的，也可引申出“空洞

   的”、“空虚的”等意思。

   1) The tree has been eaten hollow by worms.

      这棵树已经被虫子蛀空了。

   2）A tennis ball is hollow,but a base ball is solid.  

      网球是空心的，但棒球是实心的。

   3）Cinder blicks are hollow building blicks made with concrete and coal cinders.

      炉渣砖是一种空心的用混凝土和灰渣做成的建筑用砖。

   4）He was thin and his cheeks were hollow.   

      他很瘦，连面颊都凹陷了下去。

   5）The divorce lfet him with a hollow feeling inside.

      离婚使他内心感到空虚

blank  “空白的”，指没有写字、印刷或做记号的空白表面或指留待填写的空白处，可引申出

   “茫然”的意思。

   1）Please write your name in the blank space at the top of the paper.

      请把你的名字写在纸顶部的空白处。

   2）I've filled in this form incorrectly. Can I have another blank piece？   

      我把表格填错了，再给我一张空白的, 可以吗?

   3）The incident came about unexpected and my mind was completely blank at the

      time. 

      这一事件发生得很突然,当时我的脑子里一片空白。

   4）There was a blank look on his face because he did not know how to answer the

      question the manager asked.   

      他神色茫然，不知道如何回答经理的提问题。