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。

---Where is Class       ?

---It’s on the       floor.

Six; third

Sixth; third

Six; three

Sixth; three

考查数词辨析。句意：----六班在哪里？---在三楼。英语中表达序号时，如果用基数词表示：名词+基数词，如六班，Class Six;如果用序数词表示：the+序数词+名词，如三楼，即the third floor。故选A项。

The student completed this experiment to make come true         Professor Joseph had said.

that

what

when

where

考查名词性从句。句意：为了使约瑟夫教授所说的成为现实，这个学生完成了这个实验。        Professor Joseph had said作make的宾语从句，该从句中，空格处在从句中作said的宾语，表示“......所说的话”，因此应用what 引导该从句。故选B项。

I don’t want to be       else. I just want to be       .

anybody;myself

somebody;myself

everybody;me

anybody;me

考查代词。句意：我不想成为任何人，我只想做我自己。anybody 任何人，用在否定句和疑问句中；somebody某人，用在肯定句中；everybody每个人；由don’t可以判断此句是否定句，所以用anybody，表示任何人。第二个句子根据I为主语，可知用反身代词myself 我自己，根据句子意为我要做我自己，me是宾格，作宾语。故选A项。

A study shows the students who are engaged in after-school  activities are happier than        who are not.

ones

those

these

them

考查代词。句意：一项研究表明，参加课外活动的学生比不参加课外活动的学生更开心。空格处代词与the students是对应关系，可以用the ones 或者those替代。“them”指代前面提到的复数名词，不能与the students形成对应关系，“these”一般不用定语从句修饰。故选B项。

It's really           to know that there're only seven bones in giraffes' long necks.

amazingly

amazed

amazing

amazement

考查形容词辨析。句意：知道长颈鹿的长脖子上只有7块骨头，真是令人惊讶。分析句子结构可知，is是系动词，空格处需填形容词作表语。主语是It,指物，表示“令人惊讶的”，应填amazing。故选C项。

It’s his brother ______ never been to Australia. You’d better take him with you.

that is

who is

that have 　

 who has

句意：就是他的弟弟从没去过澳大利亚。你最好带他和你去。根据句意及题干分析此题是考查强调句型，因为强调的是his brother，是人，所以用who引导是现在完成时态，故选D。