So difficult __________ it to work out the problem that I decided to ask Tom for advice.

 I did find 

did I find

 I have found  

have I found

句子使用的基本句式为so…that…结构。按英语语法，当该结构的so…置于句首时，其后的句子(主句)要用倒装语序，如：So loudly did he speak that even people in the next room could hear him. 他讲话声音那么大，隔壁屋里的人都听得见。

As crossing

While you cross

While crossing

Cross

这题考查时间状语从句的省略式，当主从句的主语一样时，可以省略从句的主语和be动词，这题的while crossing就省略了you are，句意是：当你过马路时，别忘了两边看看。选C。

Why don't you             ? Try to make it a win-win situation for you both.

compromise

object

salute

rate

考查动词词义辨析。句意：你为什么妥协呢？试着为你们双方创造

双赢的局面。A.compromise妥协；B.object反对；C.salute致敬；D.rate比率。由后文试着为你们双方创造双赢的局面，可知前面讲的是妥协。故选A项。

Mary and her friend          a plan and gathered forty people from my company to help the homeless people at the Christmas party.

came up with

put up with

caught up with

kept up with

考查动词短语辨析。句意：玛丽和她的朋友想出了一个计划，在圣诞节聚会上，从我的公司聚集了四十几个人来帮助无家可归的人。A. came up with 提出；B. put up with 忍耐；C. caught up with追上，赶上；D.kept up with 跟上。下文“聚集人帮助无家可归的人”是想出的计划。故选A项。

Dr.Rowan,           secretary resigned two weeks ago, has had to do all his own typing.

whose

of whom 

of which

which

考查定语从句。句意：罗文博士的秘书两周前辞职了，他只能自己打字。          secretary resigned two weeks ago是非限制性定语从句，修饰Dr.Rowan, 引导词在从句中作定语，表示“Dr.Rowan's”，表示“......的”，应用关系代词whose引导该从句。故选A项。

I_____you can finish the exam in two hours.

does believe

do believe

did believed

do believed

句意：---我确实相信两个小时内能完成考试。这里用来强调，在谓语动词前加助动词do表示强调。句子的主语是第一人称，所以位于动词不能用单数，故排除A；did后用动词原形；do后用动词原形，故选B。

Based on the agreement,all payments          be made by the end of the month.

may

can

shall

will

考查情态动词。句意：根据协议，所有款项应在月底付清。shall用于法律，条款中表示必须要做的事。故选C项。

There's no simple solution          this problem.

of

for

to 

about

考查介词。句意：这个问题没有什么简单的解决方法。此处是短语“

the solution to....的解决方法”，应用介词to。故选C项。

Daniel has undertaken to keep the secret, so he won’t tell anyone even though ______.

asked to keep

to be asked

to ask

asked to

考查省略和过去分词。句意：丹尼尔答应保守这个秘密，所以即使问他也不会告诉任何人。此处是even though引导的让步状语从句，从句主语和主句主语都是he，和ask之间是被动关系，相同的主语和be动词可以省略，所以这里是过去分词作状语，且ask sb. to do sth.可以省略与前面相同的部分，只留下动词不定式符号to。故选D。

Don’t mention that at the beginning of the story, or it may             the  shocking end.

give out

give away

give up

give off

考查动词短语辨析。句意：不要在故事的开头提到它，否则会泄露令人震惊的结局。A. give out分发；B. give away泄露；C.give up 放弃；D. give off发出（光），根据“the shocking end”可知，此处表示“泄露”。故选B项。