第三大題 標出主題句(本大題共3小題，每小題5分，共15分)
一， 考核知識點：考查對主題句(topic sentence)特征的掌握以及識別主題句的能力。
●試題：
16. Choose the best topic sentence from the group below. Write the letter of the choice in the blank.
[A] Temperatures in the western hemisphere have stayed the same in the past century.
Temperatures in the western hemisphere are being studied by scientists.
[C] Temperatures in the western hemisphere are gradually warming.
[D] Temperatures in the western hemisphere are being changed.
●答案：
16. [C] Temperatures in the western hemisphere are gradually warming.
●解題關鍵：
(1) 了解主題句(topic sentence)的特征：主題句(topic sentence)是一個段落中最重要的句子，它的作用是概括一個段落的中心意思，所以往往是表示一般概念的句子。范圍太大或太小，都會使作者無法展開段落，必須通過某些限制性詞語將內容范圍限制到一定程度，因此主題句應包括主題和限制性詞語。從語義層次分析，主題句是一個概括性的語句(general statement)，它必須包涵段落要談論的主體(subject)和這個主體的某一所談論的方面(controlling idea)，即Topic sentence=Subject+Contrlling idea.
(2) 比較16題中的四句，看哪一句既有一定的概括性，又能留出一定的展開余地。
(3) [C]句符合上述的條件，其中Temperatures in the western hemisphere是subject； are gradually warming是controlling idea，有待推展和細節支持。
(4) 其余三句雖也符合主題句“Topic sentence=Subject+Contrlling idea”的特征，但[A]句中have stayed the same in the past century是靜態的描述，不利于推展；句中are being studied by scientists意義籠統，缺乏探討的價值；[D]句中被動語態are being changed的使用使句義不夠明晰，令人費解。
二， 考核知識點：考查在段落中尋找主題句(topic sentence)的能力。
●試題：
17. Read the following paragraph and underline the topic sentence.
I don‘t like algebra this semester， and I’m not too found of history. But I‘m enjoying my racquetball class a lot. I’m getting a lot of exercise， and I‘m also enjoying the game. We usually play partners and compete in small tournaments within the class. The competition is fun， and playing partners keeps it relaxed. I also have found that I have some ability in racquetball that I haven’t had in other sports. I may sign up for intermediate racquetball next semester.
●答案：
17. Topic sentence： I‘m enjoying my racquetball class a lot.
●解題關鍵：
(1) 段落中的主題句(topic sentence)是全段的統領，它說明段落的中心思想和作者寫作的目的。段落的其余句子必須與主題句密切相關，共同闡明、證實主題句。因此，主題句具有概括性，支配段落中其他各句的走句。
(2) 多數情況下主題句出現在段首，但也可以在段中或段尾。17題段落中的第二句I‘m enjoying my racquetball class a lot包含subject(racquetball class)和controlling idea(I’m enjoying it a lot)，下文各句就enjoying一詞展開，詳細說明喜歡racquetball class的事實和原因。所以敲定該句為主題句。
●考生典型答題錯誤分析：
(錯誤)Topic sentence： I may sign up for intermediate racquetball next semester.
(分析)該句適合做結論句(concluding sentence)，因為它必須依賴前文對enjoying my racquetball class的探討才有效度。
三， 考核知識點：考查根據段落中的支持句(supporting sentences)來推斷主題句(topic sentence)的能力。
●試題：
18. Read the following paragraph carefully and select the best topic sentence from the four possible answers that follow the paragraph.
Topic sentence：
First， there are always customers to be served. I work in a downtown McDonald‘s that gets lots of traffic， and as soon as I serve one customer， there is always another one ready to order. There is constant pressure because I can never step back for a few minutes and relax. Second， I have to put together all of the orders myself. To do that， I have to move all over the serving area： French fries on one side， drinks on the other， and burgers in middle. It’s easy to get sloppy and spill a Coke or throw French fries on the floor. Also， I must always move at a fast pace. McDonald‘s has an image to uphold， and its workers must scurry about like ants. If I don’t move fast enough， some customers will say， “Hey， speed it up，” or “I though McDonald‘s had fast service.” And with all of this nonstop work， I only get one ten-minute break every two hours. However， ten minutes isn’t enough time to rest and feel like getting back to work. It only gives me enough time to realize hoe tired I am， so I go back to work depressed. Finally， my manager really keeps the pressure on. He watches us like a hawk， and every time I do something wrong， he seems to catch it. He also has a reputation for firing people， and he never lets any of the workers feel that their jobs are safe. By the end of the day， I‘m emotionally and physically drained， like everyone else， and we all head out the door grumbling.
[A] The hamburger sold at McDonald‘s is my favorite food.
There are several reasons that I like McDonald‘s.
[C] Working at McDonald‘s is very tiring.
[D] I have no idea about working at McDonald‘s.
●答案：
18. Topic sentence： [C] Working at McDonald‘s is very tiring.
●解題關鍵：
(1) 明確主題句(topic sentence)與支持句(supporting sentence)的關系：主題句(topic sentence)是統領，起著開宗明義、提綱挈領的作用，其余的與主題相關的支持句(supporting sentences)都圍繞主題句來展開，用來闡明、證實主題句。
(2) 18題段落中的各句描述了麥當勞員工工作的情況：店員要不停地接待一個又一個顧客，異常忙碌，身體極度疲勞，還要承受顧客的諸多抱怨和經理的嚴厲監督。所有這些supporting sentences都用細節支持說明一個事實：在麥當勞工作十分辛苦。故[C]句Working at McDonald‘s is very tiring就是該段落的topic sentence.
(3) [A]、、[D]三句，與段落各支持句內容或不相關或相矛盾，故為錯解。
