1. 相同詞性的同義替換：
相同詞性的同義替換一般指的是隻涉及單個單詞的轉換。單個單詞的轉換包括詞性轉換及同義詞轉換。其中詞性轉換是相對簡單的一種，詞彙量可觀的考生自然可以遊刃有餘，輕鬆應對;即便不認識被轉換了的單詞的考生，也可以通過詞根詞綴以及上下文進行猜測。
例如：
Example 1:
One of the brain’s most difficult tasks is to
A. react to their own thoughts
B. helped create language in humans
C. respond instantly to whatever is happening
題幹中的核心資訊most difficult應該在讀題的過程中被考生捕捉到，在定位時應充分考慮到被代換的可能性;另外備考時訓練充分有素的考生還會考慮到句子結構的整體順序的不同。這樣，當定位到原文的對應資訊句：
Making a rapid emotional assessment of the events of the moment is an extremely demanding job for the brain, animal or human.
考生應該能夠敏銳地發現extremely demanding是most difficult的代換，由此確定該句所表達的意思是正確答案，在list中搜尋正確的選項時，句子中的內容被再一次代換，其中原文中 rapid emotional assessmentof the events被代換為respond instantly to whatever is happening, 至此，答案為C。
Example 2:
It has been suggested thatchildren hold mistaken views about the 'pure' science that they study at school.根據'pure'定位到文中第二段第一行Many studies have shown that children harbor misconceptions about 'pure' science, curriculum science. 短短一句話我們可以發現有三組四處同義替換，分別為suggested-shown; hold-harbor; mistaken views-misconceptions; science that they study at school-curriculum science. 因此答案為TRUE。
Example 3:
Some people may believe that the teacher- subjects’ behavior could be explained as a positive survival mechanism.
可以看出句中positive和survival是關鍵詞，由句中出現的survival mechanism可判斷為是從生物角度來談論的，又因為原文的F段首句：One’s first inclination might be to argue that there are must be some sort of built in animal aggression instinct that … 中提到了相關內容，所以定位到該段。迅速掃描，搜尋和兩個關鍵詞對應的資訊，除了在該段第六行出現了原詞重現的survival, 還在上一行出現了advantageous, 顯然是positive的代換。由於原文跟題目中的資訊吻合，所以答案是TRUE。
2. 不同詞性的同義替換：
不同詞性同義代換顧名思義，就是在代換時不受詞性的限制，比如：obvious換成clearly; similar換成resemble等。
Example 1:
Despite substantial funding,results (of this program) have been disappointing.
代換為：This program failed although they received sufficient funding.
因為把disappointing換成了failed, “although”代換了“in spite of”, 通過詞的代換就會很自然的實現英文中提倡的句式多樣性。
雅思閱讀同義詞轉換二——片語的轉換
片語的轉換一般情況下是同義詞轉換的一個衍生。當一個詞無法用另一個同義詞到位地解釋時，可能會出現用片語解釋的情況。另外如果本身就是片語的形式，那麼通常來講還是會用片語的形式進行解釋。
例如：
Example 1:
原文：Computers are gaining in popularity, despite their cost.
題目：Computers are more popular than they used to be.
原文當中的gaining in popularity題目中用more popular than they used to be作為替換。兩者在意思上屬於完全一致的同義轉換，因此答案為TRUE。
Example 2:
原文：Biologically, a species becomes extinct when its last individual dies.
題目：In biological terms, aspecies is said to be extinct when only one individual exists.
原文當中的biologically用題目的in biological terms作為替換。Become則由is said to be作為替換。但是原文當中的die在題目中變成了exist, 直接相反的意思。介於最後這一處的轉換與原文資訊不符，可以判斷出此題答案是FALSE。
Example 3:
There were several reasons for the research into plastics in the nineteenth century, among them the great advances that had been made in the field of _____and the search for alternatives to natural resources like ivory.
解析：根據nineteenth century定位到文中第二段 impetus behind the development of these early plastics was generated by a number of factors- immense technological progress in the domain of chemistry,.......其中，in the field of意思等同於in the domain of“在....領域”，因此答案為chemistry。
In recent years, many of them have been obliged to give up their _____ lifestyle, but they continue to depend mainly on _____ for their food and clothes.
解析：根據上下文定位到文中 Over the past 40 years, most have abandoned their nomadic ways and settled in the territory's 18 isolated communities, but they still rely heavily on nature to provide food and clothing. 因為大多數同學都認識abandon, 更知道give up是“放棄”的意思，屬於單詞與片語的替換，因此第一個空填nomadic, lifestyle“ 生活方式”與ways替換，depend mainly on與rely heavily on屬於片語與片語的替換，意為“依賴......”，答案為nature。
綜上所述，同義詞替換在雅思閱讀中的重要作用顯而易見。小編提醒廣大考生在平時一定要注意多積累，比如在背單詞的時候，就不能只滿足於記住單詞本身，還應該多想想這個單詞有什麼同義、近義詞，以及片語的代換，這樣在雅思閱讀中就能取得好的成績。