19 by the multitude of information systems requiring complicated access, Berners-Lee fashioned a universal one that made information readily __20__ .
答案：(B) Frustrated
Frustrated by… 是分詞構句，省略了 Being，表被動的「（他）因…而感到挫折」；Having frustrated 是主動完成式，To be frustrated 表目的，Been frustrated 不能單獨引導分詞構句。
答對率 33%。
看到句首要填動詞形式，四個選項都有 frustrat-，你大概靠語感亂猜。關鍵在於：frustrate 是「使人感到挫折」的情緒動詞，人是「被弄得挫折」的一方，所以要用過去分詞。
interest／excite／bore／surprise／frustrate 這類動詞的原意都是「使人…」，所以形容人用過去分詞（I am interested.），形容事物用現在分詞（The book is interesting.）。本句主詞是 Berners-Lee（人），當然用 Frustrated。
完整寫法是 Being frustrated by the multitude of information systems…，分詞構句裡的 Being 通常省略，只留下過去分詞。同類的還有 (Being) Born in Taipei, she…（她生於台北）。
Having frustrated 是主動完成式，會變成「他讓別人挫折」；To be frustrated 表目的，變成「為了感到挫折」，語意荒謬。
be frustrated by／with（因…而挫折）、a frustrating experience（令人挫折的經驗）、(Being) + p.p. 分詞構句（省略 Being 的被動分詞構句）、readily available（隨手可得）。
Today, with a couple of clicks, you can go anywhere in the world without leaving your computer. So it should come as little 16 that the Internet has headlined the top 25 innovations of the past quarter century, according to a panel of technology leaders assembled to promote inventiveness.
In creating the list, the group 17 twenty-five non-medically related technological innovations that have become widely used since 1980. These innovations are readily recognizable by most Americans, have had a direct impact on our everyday lives, and may also dramatically affect our lives 18.
The top innovation, the Web, was created by British software consultant Tim Berners-Lee. 19 by the multitude of information systems requiring complicated access, Berners-Lee fashioned a universal one that made information readily 20. He created HTML (hypertext markup language) and its rule of usage (HTTP, hypertext transfer protocol). In 1991 he unveiled the World Wide Web. Today, this No. 1 invention has become so commonplace that it is almost taken for granted.