If you don't understand something, you may resrarch, study, and talk to other people          you figure it out.

because

though

until

since

考查连词。句意：如果遇到不懂的东西，你可以搜索、研究，和别人交流直到弄明白。A. 因为； B. 尽管；C.until直到；D.since自从，因为。根据句意可知，until符合语境。故选C项。

It was along the Mississippi River _________ Mark Twain spent much of his childhood.

how

which

that

where

此处构成It was...that...强调句式，句中强调了介词短语along the Mississippi River。故选C。

Writing out all the invitations by hand was more time-consuing than we             .

will except

are  excepting

except

had excepted

考查时态。句意：手工写下所有的邀请函要比我们预料的花去更多的时间。根据句意可知我们预料是在实际上写之前发生的，而本句中实际写花去的时间使用了过去时was，所以expect用过去完成时。故D项正确。

It is the ability to do the job ______ matters not where you come or what you are.

one

that

what

if

考查强调句。句意：是做这项工作的能力更重要而不是你从哪里来和你是谁。此句是强调句，基本结构是It is/was+被强调部分+that，此处强调the ability to do the job，故选B.

The teacher was so pleased with the progress that I had        in my study this term that she sent me an English-Chinese dictionary.

made

had 

kept

graded

考查动词辨析。句意：老师对我在这学期在学习上取得的进步非常满意，寄给我一本英汉词典。分析可知hat I had        in my study this term 应是之前名词the progress的定语从句，先行词在从句中属于固定结构make progress“取得进步”的宾语。故选A项。