【相关点评】
以上我们选取了剑桥6 test3 section 4中的听力原文进行分析，因为场景是关于新石器时代的畜牧，农耕和陶器制作等的讲座，所以需要大量地表达对过去事实的推测，因此我们可以听到频繁地出现了情态动词+动词完成时的结构：
Could+ have done：表示“过去本来可以做某事，但实际上没有做”
Would+ have done：表示对过去事情的假设，意思是“本来会做”
Must+ have done：用于肯定句，表示“过去一定做过某事”，表示一种很有把握的推测。
除此之外，还有类似的结构，如：
should (ought to) have done ：表示过去应该做而（实际）没有做的事情,含有责备或遗憾的语气，意为“本应该……”
needn’t have done：表示过去没有必要做某事，但实际上做了某事
may／might have done：表示对过去情况的一种不太有把握的可能性推测，表示“过去可能／大概已做了某事”
分析认为，在雅思口语真题中，有大量题目都是针对过去发生的事情，所以需要表达对过去的各种推测的语气时，正需要这种结构，例如：
【真题举例】
Part 1：
When was the last time you gave flowers to someone?
Ø What subjects are you studying?
Ø Why did you choose to study that subject?
Part 2：
………………………………………………………………………………………………………………………………
Describe an antique or some other old thing that your family has kept for a long time.
You should say:
what it is
when your family first got this thing
how long your family has kept it
and explain why this thing is important to your family.
……………………………………………………………………………………………………………………………..
Part 3：
Do you agree that even very young children are under much more pressure than before to do well at school?
Have people's attitudes about recycling changed in recent years?
这种情态动词+动词完成时的结构因为在口语表达上的复杂性和实用性，所以如果烤鸭们尝试使用，绝对是雅思口语中稳拿高分的句型。
【利用指数】★★★★
很多烤鸭在使用稍复杂的口语句型时都有所保留，因为总感觉会出错，所以干脆只使用简单的语法，或是把精力都用在词汇等其他方面上，但是这些做法都无法弥补考官心中所期望的高分语法要求，其实只要考生在表达过程中努力尝试使用一些高级的语法句型，哪怕是偶尔出现了一些错误，考官给予的分数也一定比只使用简单语法的情况要高一些的。所以为了能够尽自己所能提高语法分数，我们一定要大胆尝试一些高级的语法句型。接下来，专家就带考生们一起通过一些听力真题来了解一下哪些高级语法会赢得考官的关注和好感吧。
高级语法使用（Higher Level Grammar）
七分必备语法之非真实条件句：
【听力真题】
If we were aware of what the weather would be like, say, next year, we could make sure that the farmers planted appropriate grain varieties to produce the best yield from the available rainfall.【7-3-3】
But if you could search out some silver paper to bring along to use in the sessions, you know, it’s shiny – it looks like water, that’d be great.【6-2-1】
Secondly, there is something very powerful in our need to pampered and looked after, it’s almost as If we return to being a baby, when everything was done for us and we felt safe and secure.【7-3-4】
I’d say your first two sections are spot on. I wouldn’t suggest that you change anything there, but in section three you really do need to have questions on teaching experience.【6-2-3】
【相关点评】
以上是剑桥6和7的各个section的听力真题，在其中我们听到了各种形式虚拟语气的使用，包括：
If 引导的非真实条件状语从句
表示建议,要求,命令,想法（如 suggest，advise，insist）的动词后的从句
含有as if / as though 的从句
虚拟语气可以表示说话人的一种愿望，假设，怀疑，猜测，建议等含义，因为在雅思口语的很多真题都是针对预测和建议而设置的，因此它们是不可替代的高分语法结构，例如：
【真题举例】
Part 1：
What would you recommend a tourist see in your hometown?
If you could redesign your home，what would you do?
If you could go back in time, what would you do differently?
Part 2：
………………………………………………………………………………………………..
Describe a party you would like to arrange for your friends or family.
You should say:
who you would invite to the party
when and where you would hold the party
what you (or, your guests) would do at the party
and explain why you would hold this party.
………………………………………………………………………………………………...
Part 3：
Do you think it would be a good idea to have a festival that is truly international, that is celebrated by everyone all over the world?
If you were to decide upon (or, set) an international celebration, what would it be?
所以正确并熟练地使用以上听力真题中的虚拟语气的句型，尤其是其中的“if…would”这样最基本的虚拟语气句型，是拿到语法高分的一个很重要的因素。
【利用指数】★★★★★
高级语法使用（Higher Level Grammar）
七分必备语法之情态动词完成时：
【听力真题】
The early farmers kept various animals, including cattle and sheep. There’s also evidence of pigs, but it is possible that these could have been descended from the native wild species….so we must assume that form the beginnings of Neolithic farming the number of breeding sheep would have considerably exceeded three hundred, and the national catle erd must have been of a similar size…but this method would have severely restricted the range of the colonising fleets. The sheer volume of animal transport necessary means it’s unlikely that this livestock could have been brought from anywhere further than England…the body of the plough would have been of wood and could have been drawn by people, but it’s also likely that cattle were used… however, after the axe had been chipped into shape, they needed water and sand for grinding and polishing, so a high mountainside wouldn’t have been an appropriate place for this. So this final stage of the manufacture must have been carried out close to water and sure enough, there’s ample evidence of this at coastal sites… after firing, the outside was often polished. This would have helped the pots of retain water, as they weren’t glazed… this could have been an limitation of earlier vessels which were made of leather sewn onto wood.
