TPO18 聽力 最後一篇lecture - 英檢

這篇好難...錯的一蹋糊塗
我想問第一題
what is the main purpose of the lecture?
A.To explain the biological advantages of a physical change that occurs in
North American wood frogs
B.To explain why the North American wood frog's habitat range has expaned
C.To describe the functioning of the circulatory system of the North American
wood frog
D.To introduce students to an unusual phenomenon affecting North American wood
frogs

我選A 答案是D
我還是搞不懂為何是D
D的敘述是說一個少見的現象影響forg
這樣感覺是說外來的事物影響frog
但是這篇主要在說frog會在冬天結凍
感覺A比較符合
請高手幫忙一下 謝謝!!

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