When a molten metal or metallic alloy is cooled to a solid, a crystalline structure is formed that depends on the particular alloy composition. In contrast, molten nonmetallic glass-forming materials, when cooled, do not assume a crystalline structure, but instead retain a structure somewhat like that of the liquid--an amorphous structure. At room temperature, the natural long-term tendency for both types of materials is to assume the crystalline structure. The difference between the two is in the kinetics or rate of formation of the crystalline structure, which is controlled by factors such as the nature of the chemical bonding and the ease with which atoms move relative to each other. Thus, in metals, the kinetics favors rapid formation of a crystal line structure, whereas in nonmetallic glasses the rate of formation is so slow that almost any cooling rate is sufficient to result in an amorphous structure.
11. The author implies that the rate at which the molten materials discussed in the passage are cooled is a determinant of the
(A) chemical composition of the resulting solids
(B) strength of the chemical bonds that are formed
(C) kinetics of the materials' crystalline structure
(D) structure the materials assume
(E) stability of the materials' crystalline structure
12. It can be inferred from the passage that, theoretically, molten nonmetallic glasses assume a crystalline structure rather than an amorphous structure only if they are cooled
(A) very evenly, regardless of the rate
(B) rapidly, followed by gentle heating
(C) extremely slowly
(D) to room temperature
(E) to extremely low temperatures
13. Select the sentence in which the author illustrates the causes of the rate of formation of the crystalline structure.
結構分析：
When a molten metal or metallic alloy is cooled to a solid, a crystalline structure is formed that depends on the particular alloy composition. In contrast, molten nonmetallic glass-forming materials, when cooled, do not assume a crystalline structure, but instead retain a structure somewhat like that of the liquid--an amorphous structure.
兩句一起看之後點出了本文兩的主角，利用In contrast轉折詞，來使得兩主角（metallic，nonmetallic）屬性相反，來簡單抓一下他們在互相比什麼，我看接下來的文字應該都可以忽略了，因為主角結論一起出現『晶體結構VS.亂七八糟』
At room temperature, the natural long-term tendency for both types of materials is to assume the crystalline structure.
給出條件，而這條件是跟主題句的溫度不太一樣，所以是在說明細節用的，而且the natural long-term tendency for both types of materials，這個已經把金屬和非金屬的物質和在一起當作形容詞修飾長期趨勢，那這就是細節的東西了，已經建立在主角之下的內容，所以沒必要知道。
The difference between the two is in the kinetics or rate of formation of the crystalline structure, which is controlled by factors such as the nature of the chemical bonding and the ease with which atoms move relative to each other.
這也是細節，但是這細節有點“不一樣”，因為difference哈哈，沒錯，因為不一樣意味著兩個東西的比較，本文章至此有再說『不一樣』的內容只有開頭的兩句話，那個In contrast, 引導的，所以表示這不同的原因在哪，所以多看這一句把原因順便記一下。
Thus, in metals, the kinetics favors rapid formation of a crystal line structure, whereas in nonmetallic glasses the rate of formation is so slow that almost any cooling rate is sufficient to result in an amorphous structure.
下結論，回到原主題討論的東西，也不用理會，光是一開頭the kinetics 就重複上句話了。
11. The author implies that the rate at which the molten materials discussed in the passage are cooled is a determinant of the
(A) chemical composition of the resulting solids
(B) strength of the chemical bonds that are formed
(C) kinetics of the materials' crystalline structure
(D) structure the materials assume
(E) stability of the materials' crystalline structure
解題：
推理題，所以找到對比對象，不過這次簡單了，因為determinant讓我們不用邏輯取反或取同，the rate冷卻速度取決於？？，有提到冷卻的就是diff那一句，換句話說，其實就是找座標系原點拉，然後就可以知道met是晶體態，假設結構整齊是Ｘ>0，所以金屬為證，另一方面，非金屬玻璃，就是Ｘ<0，砸亂不堪。
The difference between the two is in the kinetics or rate of formation of the crystalline structure, which is controlled by factors such as the nature of the chemical bonding and the ease with which atoms move relative to each other.
那怎麼把它變成答案了，determinant＝controlled，所以後面的內容去跟選項連連看即可： the nature of the chemical bonding and the ease with which atoms move relative to each other.結構上面的變動容易度，所以就是（Ｄ）在描述著某種物理變化，（Ａ）這是化學變化，化合物『成分』不是，當然要驗算也是可以透過文章主題句的structure來判斷，選（Ｄ）
12. It can be inferred from the passage that, theoretically, molten nonmetallic glasses assume a crystalline structure rather than an amorphous structure only if they are cooled
(A) very evenly, regardless of the rate
(B) rapidly, followed by gentle heating
(C) extremely slowly
(D) to room temperature
(E) to extremely low temperatures
解題：
又來推理題，對比對象也找好了，a crystalline structure rather than an amorphous structure
所以找到whereas in nonmetallic glasses the rate of formation is so slow that almost any cooling rate is sufficient to result in an amorphous structure.
文章這句話出現異形amorphous structure ，看看前後面給啥內容，我們再取反就是答案了，that almost any cooling rate is sufficient這『取反』就是冷卻『速度不夠』，輕輕鬆鬆分數入袋，選（Ｃ）
13. Select the sentence in which the author illustrates the causes of the rate of formation of the crystalline structure.
這題考點跟第一題一樣，找到the rate of formation的原因，這個原因就是接到The difference between the two........by factors
The difference between the two is in the kinetics or rate of formation of the crystalline structure, which is controlled by factors such as the nature of the chemical bonding and the ease with which atoms move relative to each other.
以上筆記供大夥參考若有錯誤再煩請指教
留言列表
托福TOEFL ibt (4)
{{ article.title }}
