Taiwan is located along the southeast coast of the Asian continent, on the line 22 the Euro-Asian and Philippine continental plates meet.
答案：(D) where
關係副詞 where 引導地方子句，「歐亞板塊與菲律賓板塊交會的『線』」，where修飾地方名詞line；that、what、when都不合這種地方關係子句的用法。
本題大考中心未公布逐題答對率，以下不談數據，只談觀念。
先行詞是 line（線），不是你熟悉的 place 或 country，所以「地方用 where」可能不會想到這條規則，反而選了最常用的 that。
先看空格前面：on the line ___ ——先行詞是 the line，指的是地理上的一條線（板塊交界線），性質上是一個「地方」。再數空格後面那個子句：the Euro-Asian and Philippine continental plates meet（歐亞板塊與菲律賓板塊交會）——主詞是兩個板塊、動詞是 meet，而 meet 在這裡是不及物的「交會」，不需要受詞，成分一個都不缺。既然不缺，that 就進不來：關係代名詞一定要在子句裡占一個位置。剩下能用的是關係副詞 where——它本身不占成分，只代替一個表地方的介系詞片語。還原一次就清楚了：on the line, and the plates meet on that line（在那條線上，而兩個板塊在那條線上交會），把 on that line 換成 where。同判準的題目題庫裡已經出現好幾次：83 年第 17 題、89 年第 25 題、92 年第 25 題、98 年第 23 題，全都是先行詞是地方、子句成分已滿。先行詞是不是典型的「地方」不重要，重要的是它在子句裡扮演什麼角色。
that：關係代名詞，成分已滿塞不進去。when：關係副詞，但要配時間的先行詞（the day when），而 line 不是時間。what：不能當關係代名詞，它前面不能有先行詞。
the line where …（……的那條線）、the place where …（……的地方）、be located along（位於……沿線）、continental plates（大陸板塊）、a geographic location（地理位置）、result in（導致）。
Are you looking for a place where the waters are clear and the skies are blue, and countless stars cover the sky at night? Or would you like to 21 through remote and picturesque fishing villages? Then pack your bags and visit the offshore islands of Taiwan!
Taiwan is located along the southeast coast of the Asian continent, on the line 22 the Euro-Asian and Philippine continental plates meet. This unique geographic location and frequent earthquake activity not only created an extremely diversified landscape and natural environment on Taiwan, but also resulted 23 the diverse traits of its offshore islands.
The main offshore islands consist of Penghu, Green Island, Orchid Island, Kinmen, Mazu, Turtle Island and Little Liuqiu. 24 their locations, land characteristics, and human activity differ, each has its own unique scenery and culture. Therefore, each island offers something different for visitors. 25 you prefer to explore nature or history, or go shopping or sport fishing, you can do it all here!