4. What 引导的名词性从句来源：考试大

　　解题要点：what兼先行词和关系代词双重身份，即what = the thing (things) that…。因此考生应特别注意，what既已包含先行词在内，它的前面就不应该再出现先行中心名词。What 与that 的区分是TOEEL常考题目

　　全真例题分析
(1) During the eighteenth century, Little Turtle was chief of the Miami tribe whose territory became ------- is now Indiana and Ohio.
(A) there
(B) where来源：考试大
(C) that
(D) what (93.5)
[答案] D what = the area that。What所指代的是地点、位置。然而，此句却不可选择（B）where。因为关系副词where不能作从句的主语。只有what即是先行词又是关系代词。

(2) The chief foods eaten in any country depend largely on ------- best in its climate and soil.
(A) it grows
(B) what grows来源：考试大
(C) does it grow
(D) what does grow (90.1)
[答案] B what grows = the thing that grows…另请注意：介词后面通常不能接that引导的从句，但可接what引导的名词性从句。

(3) A hinge joint is ------- permits the forward and backward movement of a door.
(A) the来源：考试大
(B) what
(C) those
(D) whose (88.10)
[答案] B what = the thing that…

(4) Essentially, a theory is an abstract. Symbolic representation of ------- reality.
(A) what it is conceived
(B) that is conceived
(C) what is conceived to be来源：考试大
(D) that is being conceived of (89.5)
[答案] C what = the thing that (is conceived to be…) .答案（A）中的代词it是多余的，因为what本身即已包含了先行词（the thing ) 和关系代词(that) 。答案（B）中的关系代词that引导的从句不可以置于介词的后面。

(5) Most of the food what elephants eat is brought to their mouths by their trunks. (93.10
[答案] B what应改为that。此句已含有先行词food，不能再用关系代词what。

　　5. 主句和从句来源：考试大

　　解题要点 主语从句是TOEEL常考而中国考生又较陌生英文文法结构。有关主语从句的命题几乎全部集中在structure (1-15题）中。主语从句的特点是读起来有种头重脚轻的感觉，而且有两个谓语动词。连词That 引导的主语从句应特别留意。因为That 在句中没有任何意义，它只具有引导出主语从句的功能，因而很容易被忽略。

　　全真例题分析
(1) ------- xenon could not from chemical compounds was once believed by scientists.
(A) For
(B) It was
(C) That
(D) While (91.1)
[答案] C That引导的主语从句。其中第一个谓语动词could from 是从句的谓语，第二个系动was是主句的谓语。

(2) ------- to space travelers is high acceleration of deceleration forces.
(A) Danger can be
(B) They can be dangerous
(C) What can be dangerous来源：考试大
(D) While danger (93.1)
[答案] C what引导的主语从句。What既是从句的连词，又是从句的主语。

(3) ------- has been a topic of continual geological research.
(A) Did the continents originate
(B) How did the continents originate
(C) Have the continents originated来源：考试大
(D) How the continents originated (91.1)
[答案] D How 引导的主语从句。

(4) ------- progress helps to relieve scarcities is a fact accepted by economists.
(A) Technological来源：考试大
(B) That technological
(C)Although technological来源：考试大
(D)There is technological
[答案] B. That 引导的主语从句，当连续读到两个谓语动词(e.g. Helps…is)，而空格在句首，应首先考虑主语从句。这是主语从句典型的句子结构。