语法填空之从句
一、名词性从句
1.正确分析句子成分是做对题的关键。
2.连接词的特点：
that没有意义，在从句中只起连接作用，不充当句子成分；
  whether, if 表“是否”，在从句中只起连接作用，不充当句子成分；
  what, which, how, where, when, whatever等，有各自的意义，在从句中担任成分。
3. that 引导主语、表语、同位语从句时不省略；有多个that引导的宾语从句时，只有第一个that可省略；引导的宾语从句中含有从句时，也不省略。
4. 介词后一般不接that引导的宾语从句，此时需要用it作形式宾语；某些动词enjoy, hate, have, like, love, appreciate, take也不能接that引导的宾语从句，此时需要用it作形式宾语。
如：You may rely on it that he will come on time.
5. reason做主语时，表语从句只能用that引导。
6.doubt 在肯定句中其后的宾语从句常用whether, if 引导；doubt在否定和疑问句中其后的宾语从句常用that引导。
如：There is some doubt ___ _______ he will come tomorrow.
7. 与if相比较，whether 引导所有名词性从句，也可用于连接介词后的宾语从句，可以discuss, decide 后引导宾语从句，还可与or not 连用。
*考题检验
1. __________ Barbara Jones offers to her fans is honesty and happiness.
2. There is clear evidence ________ the most difficult feeling of all to interpret is bodily pain.
3. World Aids day is also important in reminding us that HIV has not gone away, and _______ there are many things still to be done.
4. News came from the school office _________ Wang Lin had been admitted to Beijing University.
5. I was close to being killed the other day. A car passed me at ________ I thought was a dangerous speed.
6. There is no doubt _________ John will support you.
7. Could I speak to ________ is in charge of International Sales please?
8. We have offered her the job, but I don’t know _________ she will accept it.
reported
9. Twenty students want to attend the class that aims to teach ________ to read fast.
10. I am afraid he’s more of a talker than a doer, which is ________ he never finish anything.
11. As far as I can see, there is no possibility ________ he will win the tennis match this time.
篇章训练： American scientists have discovered that walnut trees can produce more than walnuts. The scientists say walnut trees also can make a chemical form of the popular pain-killing medicine aspirin. The trees do this under the stress of disease 1_________ other threats. Scientists say the chemical may help the trees reduce damage from dry weather, unseasonable temperature 2_______ other changes in the environment.
  The results are important 3__________ presence of the chemical could warn growers early 4_____ a tree is in danger. Growers could recognize a problem 5________ leaves on walnut trees die and fall off. The scientists say the 6________(find) also show that a plant can communicate with other plants through the atmosphere. For example, a tree could communicate 7_______ it is under attack from insects. 8_______ that information, a grower could begin corrective treatment. 
  Researchers 9________(know) for a long time that laboratory plants may produce methyl
salicylate, aspirin’s chemical form. Aspirin was first made from the bark covering on willow trees. 10_______ the researchers had never before found methyl salicylate in a forest. They have not confirmed that trees could emit, 11_______ give out, large amounts of the chemical into the atmosphere.
二、定语从句
*做题指导
1. 正确分析句子成分是做对题的关键。
2. 引导词的特点：
  *关系代词：which, that, who, whom, whose； 关系副词when, where, why 和that。（略）
*that既指人又指物，先行词是everything, all等或有 the first, the most, the very 等修饰时都能用，所以一般情况下用that引导定语从句比较保险，但以下情况不能用，切记：
  a. 在非限制性定语从句中（从句前面有逗号与主句隔开），用which或who, whom;
  b. 前面有介词时，用which 或whom;
  c. 前面的先行词是anyone, those 时， 用who；
  *as 和which 可以引导非限制性定语从句，指代整个句子（which有时也仅仅指代主句的一个词和一部分）。which引导的这种从句只能放在主句后，as 引导的这种从句可以放在主句前、后、或在中间插入。另外，以下短语几乎成为固定搭配：as is often the case, as is known to all, as is hoped, as is natural, as is reported, as has been said, as we know。
  如：_______ is announced in today’s newspapers, all the schools will reopen on Sept. 1st.
  *当先行词为case, situation, condition, point 时， 且从句不缺少主要成分，用where引导；而出现occasion常用when;
  * 关系副词where, when 有时用作关系代词；
    如：He climbed up to the top of the temple, from where he could see nothing but trees.
  * which 偶尔也指人，着重于该人的品质，地位，身份，而不是人本身。
    如：Her sister has become a lawyer, which she wants to be.
  *比较：
  a. There are 20 people in the bus, most of ________ are boys.
  b. There are 20 people in the bus, most of ________boys.
  c. There are 20 people in the bus and most of _______ are boys.
    key: whom/ them/them
  * 比较：
  a. ______ is known to us all, the earth goes around the sun.
  b. ______ is known to us all is that the earth goes around the sun.
  c. ______ is known to us all that the earth goes around the sun.  Key: As/ What/It