Business, however, was not 27 he had expected. 28 , as he sat in a cafe in a small town, he had an idea.
答案：(A) One day
One day 是敘事故事開頭常用的說法，表示「有一天」；Another day（語意不通，這是新故事的開端不是「另一天」）、Someday（指未來某一天，時態不合，這裡講的是過去發生的事）、The other day（前幾天，通常搭配現在視角回憶）都不如 One day 自然合適。
本題大考中心未公布逐題答對率，以下不談數據，只談觀念。
四個選項的中文都可以說成「某一天」，光比中文完全分不出來。這一組是英文裡最容易混淆的時間片語之一，必須靠它們各自指向的時間來分。
先看這一句在故事裡的位置：前面交代 Levi Strauss 帶著帆布到加州、生意卻不如預期；本句 ___ , as he sat in a cafe in a small town, he had an idea.（……，他坐在小鎮的一家咖啡館裡，忽然有了一個點子。）這是敘事往下推進、引出一個新事件的地方，英文的固定說法是 One day（有一天）。順便把這四個一次分清楚：One day：故事裡的「有一天」，指過去某一天，也可以指未來某一天。The other day：前幾天、不久前的某一天，指的是最近的過去。Someday：將來的某一天，只能指未來。Another day：改天、另外找一天，通常用在改約或延期。
The other day（前幾天）：指的是說話當下不久之前，而這是十九世紀的故事，時間點對不上；而且敘事引出新事件不用這個說法。Someday（將來某一天）：只能指未來，但整段是過去的敘事。Another day（改天）：用在改約或延後，本句不是在改期。
One day（有一天，敘事常用）、The other day（前幾天）、Someday（將來某一天）、Another day（改天）、sit in a cafe（坐在咖啡館裡）、have an idea（有了一個點子）。
When Levi Strauss arrived in the United States from Bavaria, he was only seventeen, poor, and knew very 21 English. Like most immigrants, he was 22 a better life. So, when gold was discovered in the West in 1849, he 23 thousands of others and rushed to California.
24 he planned to open a shop in San Francisco, he took many goods with him, 25 a large quantity of canvas. He hoped to sell 26 as material for tents or wagon covers. Business, however, was not 27 he had expected.
28 , as he sat in a cafe in a small town, he had an idea. He saw a man with a hole in the leg of his trousers and 29 realized what Californians 30 for the rough work they were doing—good, strong trousers!