[求助] questions about structure........

hazard

I almost lose my confidence when I test structure. ( 12 of 40 are incorrect )

1. The most important chemical catalyst on this planet is chlorophyll, ----- carbon dioxide and water react to form carbohydrates.
(c) presenting
(d) in the presence of which
ANS: D.....................why can't choose (c) ?

2. ----- at this site of a fort established by the Northwest Mounted Police, Calgary is now one of Canada's fastest growing cities.
(a) built
(c) To build
ANS: A.....................why C can't ?

3.In the United States during the Second World War, ( each ) trade unions ( and ) employers avoided federal limits on wages ( by ) offering ( employees ) nontaxable medical benefits.
ANS: A ........I know there is one incorrect between a and b....But I chose b......>"<
         help me please.......ToT
4. Some marine invertebrates, ( such as the ) sea urchin and the starfish, ( migrates ) from deep water ( to shallow ) during spring and early summer (  to spawn )
ANS: A............why B is correct ?????

5. Marshes, wetland ( areas characterized) by (plant grassy) growth, are distinquished (from) swamps, wetlands (where trees) grown.
ANS: B......... the correct is " grassy plant growth " ?
              but is there correct  adj. + n + n ?      and adj. + adj. + n  correct too ?

6. Wampum, beads used as (a form) of exchange (by ) some Native Americans, was made of (bits of) seashells cut, (drill), and strung into belts.
ANS: C ..................I choose D.................>"<

7. Proper city planning (provides for) the (distribution) of public utilities, public buildings, parks, and (recreation centers), and for adequate and (the inexpensive) housing.
ANS: D........I choose A......cuz provide to.......@.@"

Anyway, also I am a little frustrated, I have many freinds here......
UP up...

Diana

Hazard，别泄气，慢慢来，没有人天生是大牛。我们一起努力。

1. The most important chemical catalyst on this planet is chlorophyll, ----- carbon dioxide and water react to form carbohydrates.
(c) presenting
(d) in the presence of which
ANS: D.....................why can't choose (c) ?

※※※※只从语法结构上看，如果选C，presenting……是分词短语修饰chlorophyll，而后面的react是谓语动词，结构错误；D则是跟一个从句，才是正确选择。

2. ----- at this site of a fort established by the Northwest Mounted Police, Calgary is now one of Canada's fastest growing cities.
(a) built
(c) To build
ANS: A.....................why C can't ?

※※※※本句中是Calgary这个城市被built，而不是Calgary建造了什么。A选项中built是过去分词。

3.In the United States during the Second World War, ( each ) trade unions ( and ) employers avoided federal limits on wages ( by ) offering ( employees ) nontaxable medical benefits.
ANS: A ........I know there is one incorrect between a and b....But I chose b......>"<
         help me please.......ToT

※※※※这个就是单复数问题吧。each后面应该跟单数名词（trade union）。each of后跟复数。

5. Marshes, wetland ( areas characterized) by (plant grassy) growth, are distinquished (from) swamps, wetlands (where trees) grown.
ANS: B......... the correct is " grassy plant growth " ?
              but is there correct  adj. + n + n ?      and adj. + adj. + n  correct too ?

※※※※我想应该改成plant grass growth，名词修饰名词。

6. Wampum, beads used as (a form) of exchange (by ) some Native Americans, was made of (bits of) seashells cut, (drill), and strung into belts.
ANS: C ..................I choose D.................>"<

※※※※这题我也不太清楚，如果是seashells 后面省略了to be，drill的过去分词是原形吗？……请哪位高手看看。

7. Proper city planning (provides for) the (distribution) of public utilities, public buildings, parks, and (recreation centers), and for adequate and (the inexpensive) housing.
ANS: D........I choose A......cuz provide to.......@.@"

※※※※D中的the应该去掉，这里adequate 和inexpensive是并列修饰housing。

个人意见，请大家讨论：）

hazard

Diana,
thanks for your encourage
I'll success oneday.......^^"
Let's beat the ETS