The submarine cables require extra 19 to install.
答案：(C) care
require extra care（需要額外的小心／謹慎）表示海底電纜的安裝需要格外謹慎，呼應後文必須避開珊瑚礁、沉船等障礙物；speed／light／link 均不符合此處語意。
care 這個字，你的印象大概只有動詞的「在乎、關心」（I don't care.）或 take care of 的「照顧」，很難把它跟鋪設電纜連起來。句子又短，The submarine cables require extra ___ to install. 四個名詞放進去讀起來都成句，於是就變成憑感覺挑。
先用形態刷一次：link 是可數名詞，extra link 前面少了冠詞、後面也沒有變複數，形態本身就不完整，可以直接出局。剩下三個都能當不可數用，得靠字詞搭配定案：require care 是很穩的組合，意思是「需要小心處理」，extra 再加強一層就是「格外小心」。care 當不可數名詞時正是「小心、謹慎」，掛鉤是紙箱上常看到的 Handle with care.（小心輕放）。往下讀一句就能驗算：They must generally be run across flat surfaces of the ocean floor, and stay clear of coral reefs, sunken ships, fish beds…（必須沿著海床平坦處鋪設，並避開珊瑚礁、沉船、魚群棲息地），整句都在講施工時要多小心。答對率四成七，鑑別度 68 是本批最高的一題，分的正是有沒有動手往下讀一句去確認，還是停在四個名詞的中文意思上猜。
speed（速度）方向相反，下一句列出那一堆要避開的東西，說明的是慢工細活而不是求快。light（光）會讓人聯想到最後一段的 fiber-optic cables（光纖電纜），但那是電纜運作時用光傳訊號，不是安裝時需要光；看到一個剛剛好像看過的選項，那正是要停下來驗算的訊號，不是選它的理由。link（連結）除了形態不完整，語意也繞回自己：電纜本身就是 link，說「安裝需要額外的連結」等於什麼都沒說。
require extra care（需要格外小心）、handle with care（小心輕放）、with care（小心地）、take care of（照顧、處理）、install a cable（鋪設電纜）、a fiber-optic cable（光纖電纜）
When we stream the latest TV series, or download high-resolution photos, we are probably unaware that the data behind them is speeding around the world in cables under the sea.
These cable systems, faster and cheaper than satellites, carry most of the intercontinental Internet traffic. Today, there are over 420 submarine cables 16 , stretching over 700,000 miles around the world. It is not a new phenomenon, 17 . The first transcontinental cable—laid in 1854—ran from Ireland to Newfoundland, and made telegraph communication possible between England and Canada. Currently, the world's highest-capacity undersea Internet cable is a 5,600-mile link between the US and Japan. 18 named "FASTER," the cable connects Oregon in the US with Japan and Taiwan.
The submarine cables require extra 19 to install. They must generally be run across flat surfaces of the ocean floor, and stay clear of coral reefs, sunken ships, fish beds, and other general 20 . The fiber-optic cables are also very fragile, so they are surrounded with layers of tubing and steel to prevent damage.