在托福英语语法当中，条件句可分为两类，一类是真实条件句;另外一类是非真实条件句，因为假设的情况不太可能发生，因此要用虚拟语气。在托福考试中，阅读部分常常使用这类词句，虚拟语气还会与倒装句双结合，难度较高，是冲高分的学生要突破的一个难点。虚拟语气又分为对过去、现在、将来事实的相反假设，因为篇幅和托福阅读的重点在于对过去事实的相反假设，因此本文就来重点讨论这种情况,希望大家能把握托福备考的这段时间。

虚拟语气和倒装句结合

虚拟条件句的从句部分如果含有were, should, 或had, 可将if省略，再把were, should或had 移到从句句首，实行倒装。

1) If I had got there earlier, I could have met her.

= Had I got there earlier, I could have met her.

= I could have met her had I got there earlier.

2) If he had taken my advice, he would not have made such a mistake.

= Had he taken my advice, he would not have made such a mistake.

= He would not have made such a mistake had he taken my advice.

托福阅读真题是如何运用虚拟语气的?

Just as painted designs on Greek pots may seem today to be purely decorative, whereas in fact they were carefully and precisely worked out so that at the time, their meaning was clear, so it is with Chinese pots. To twentieth-century eyes, Chinese pottery may appear merely decorative, yet to the Chinese the form of each object and its adornment had meaning and significance. The dragon represented the emperor, and the phoenix, the empress; the pomegranate indicated fertility, and a pair of fish, happiness; mandarin ducks stood for wedded bliss; the pine tree, peach, and crane are emblems of long life; and fish leaping from waves indicated success in the civil service examinations. Only when European decorative themes were introduced did these meanings become obscured or even lost.

Question:11. Paragraph 5 suggests which of the following about the decorations on Chinese pottery?

A. They had more importance for aristocrats than for ordinary citizens.

B. Their significance may have remained clear had the Chinese not come under foreign influence.

C. They contain some of the same images that appear on Greek pots.

D. Their significance is now as clear to twentieth century observers as it was to the early Chinese.

经过之前对语法的讲解，我们可以发现选项B是一个虚拟语气+倒装句的用法，应该翻译成“如果中国没有经历西方的影响，它们的重要性本来能清晰保存下来的。”，对应原文最后一句Only when European decorative themes were introduced did these meanings become obscured or even lost. 因此B是正确选项。

Yet it may be incorrect to lay the blame entirely on human action. Several of the lowland cities, such as Tikal, appear to have depended heavily on the cultivation of raised fields set in the marshy depressions known as bajos, which today flood intermittently in the rainy season but may originally have been permanent lakes. The raised-field system of intensive cultivation (created by digging surrounding canals and using the soil removed to elevate the fields for planting) allows year-round food production through the constant supply of soil nutrients that erode into the drainage ditches dug around the raised fields, nutrients that are then collected and replaced. Stable water levels were essential to this subsistence system, but evidence from Lake Chichancanab in Yucatán shows that between A.D. 800 and A.D. 1000 this region suffered its driest period of climate in several thousand years. We may expect that as a result water levels fell, and the raised fields in many areas became unusable. But the human response must be viewed through the lens of the social, political, and cultural circumstances. These exerted a powerful mediating effect on the way the Maya endeavored to cope with their difficulties. Had population levels been lower, the impact of the drought may not have been catastrophic, as it was, the Maya were already reaching the limits of the available subsistence capacity, and Mayan elites had espoused certain social and political agendas (including expensive warfare and competition with each other). It was against this specific background that a period of drought led quickly to crisis and collapse.

Question: According to paragraph 5, all of the following made it more difficult for the Maya to cope with the effects of the drought EXCEPT

A. failure to properly cultivate the fields

B. high population levels

C. competition between Mayan groups

D. warfare

很多同学会因为没读懂原文”Had population levels been lower, the impact of the drought may not have been catastrophic”而错选B，但其实原文的意思是“如果人口少一点，干旱的影响本来不会如此灾难性的 ”也就是说玛雅文明很难对付干旱是因为它人口很多，这又是个排除题，因此不能选B。

对待托福考试中任何一部分都需要大家在备考时就注重基础，用心学习，了解托福考生在阅读考试中需要知道的地方，避免丢分影响总分的成绩。最后深圳新航道小编希望各位考生都能考到理想的分数。