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。

It was the typhoon           was called Tiange           hit Zhuhai and Macao.

which; that

what; which

that; who

that; which

考查定语从句和强调句型。句意：袭击珠海和**的是“天阁”的台风。此处typhoon是先行词，指物在后面的定语从句中做主语，所以第一空填which/that；第二空是强调句句型，It is/was+强调部分+that（指人也用who）+其他，这里typhoon指物。所以第二空填that。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。

Small sailboats can easily turn over in the water ________.

if not managed carefully

if are not managed carefully

unless not managed carefully

unless are not managed carefully

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.

Only after my friend came ______.

did the computer repair

he repaired the computer

was the computer repaired

the computer was repaired

句意：直到我的朋友来了之后电脑才被修理。放于句首的only修饰时间状语从句after my friend came，主句应进行部分倒装，将助动词was提到主语前面，故选C项。