One morning in 1928, this 16 proved very fortunate.
答案：(D) disorder
disorder 在此是「凌亂、無秩序」，回指前一句所說 Fleming 的實驗室一向雜亂：某天早晨，這份凌亂反倒成了幸運；merit（優點）、opinion（意見）、scandal（醜聞）都與前文接不上。
答對率 30%。
disorder 你大概只記得「疾病、失調」（eating disorder 飲食失調），沒想到它的字面就是 dis-（否定）＋ order（秩序）——也就是「凌亂、無秩序」。把字拆開，這個意思其實很直觀。
Fleming had long been known for having an untidy laboratory.（弗萊明一向以實驗室雜亂出名）——untidy 就是 disorder 的同義改寫。本句用 this ___ 回頭指稱前一句講的那件事，這叫「概括性名詞回指」：用一個名詞把前面整句話收攏起來。遇到 this ＋ 名詞的空格，先回頭看前一句在講什麼，答案通常是那句話的濃縮。
下一句說那天是他休長假後回來上班的第一天，接著就發現了盤尼西林——正是因為實驗室亂、培養皿沒收，黴菌才有機會長出來。
disorder（凌亂、無秩序／失調）、in disorder（雜亂無章）、be known for（以…出名）、untidy（凌亂的）、a stroke of luck（意外的好運）。
Scientific discovery can take various forms. One of them is "serendipity," the luck of finding valuable things unintentionally. Serendipity was at work when Alexander Fleming discovered penicillin, the antibiotic miracle.
Fleming had long been known for having an untidy laboratory. One morning in 1928, this 16 proved very fortunate. It was his first day coming back to work after a long vacation. Before the vacation, he 17 in the sink a number of petri dishes in which he had been growing bacteria. While he was sorting through the long 18 dishes of germs that morning, he observed that some of the dishes were contaminated with a fungus, which had ruined his experiment. He was about to 19 the dishes, but he noticed that in one dish, the bacteria had failed to grow in the area around the fungus. This accidental finding gave rise to subsequent research that led to the discovery of penicillin—a drug that has since saved millions of lives.
Chance 20 , however, may not be enough to make key discoveries like this. The scientist must have a prepared and open mind to detect the importance of the unforeseen incident and to use it constructively.