The new panel is not the first of its 18 , but it may be the most flexible—it bends like paper.
答案：(A) kind
【句型】the first of its kind 字詞搭配「同類中的第一個」，表示這種新面板不是同類產品中的第一個；source（來源）、role（角色）、price（價格）都不合。
本題大考中心未公布逐題答對率，以下不談數據，只談觀念。
四個選項都是名詞，如果沒認出 the first of its ___ 是一個固定說法，會開始猜「第一個來源」「第一個角色」，怎麼想都不對。
四個選項都是名詞，可見這一格考的是搭配。整句是 The new panel is not the first of its ___ , but it may be the most flexible（這款新面板不是同類中的第一個，但可能是最柔軟的）。the first of its kind 是固定說法，意思是「同類產品中的第一個、首創」。再用後半句驗算：but it may be the most flexible——既然要說「雖然不是第一個，但可能是最柔軟的」，前半自然是在跟「同類的其他產品」比，kind（種類）完全吻合。順便記一下同一組：the first of its kind（同類中的首創）、one of a kind（獨一無二）、of this kind（這一類的）。
source（來源）：the first of its source 不成說法。role（角色）、price（價格）：兩個都與「同類產品」這個比較的範圍無關。
the first of its kind（同類中的第一個）、one of a kind（獨一無二的）、a kind of（一種）、flexible（有彈性的、可撓的）、bend like paper（像紙一樣彎折）、per square meter（每平方公尺）。
Solar panels can turn sunlight into electricity. Conventional solar panels are 16 crystallized silicon, the same material used in computer chips. But silicon is expensive and the panels are heavy. Facing this 17 , engineers at a Japanese company have developed a thin-film flexible solar panel. The new panel is not the first of its 18 , but it may be the most flexible—it bends like paper.
At one kilogram per square meter, this new type of panel weighs one tenth of conventional solar panels. 19 means it could be used in novel places, such as the roof of a tent, the walls of a building, or the top of a bus. Sheets of the material could be used to make portable, rollable battery chargers for mobile electronic 20 , like notebook computers or cellphones. As many countries are now pushing for green technology, the new flexible solar panels may spur a great demand.