Usually a stye is accompanied by a swollen eye. 19 a stye can look unpleasant at times, it is usually harmless and doesn’t cause vision problems.
答案：(D) Although
語意讓步：「雖然針眼有時看起來令人不舒服，但它通常是無害的」，Although（雖然）符合這個讓步轉折；As（當……時候/因為）、If（如果）、Unless（除非）都不合。
四個選項都是連接詞，你可能會直覺挑 As，因為 As 又能表「當……的時候」又能表「因為」，看起來最保險。但這一題的關鍵不在單字意思，而在前後兩個子句是同方向還是反方向。
把兩個子句拆開讀。前半：a stye can look unpleasant at times（針眼有時看起來令人不舒服）——負面。後半：it is usually harmless and doesn't cause vision problems（通常無害，也不會造成視力問題）——正面。一負一正，是明顯的讓步轉折，所以選 Although（雖然）。驗算方式：換成 Even though 或 Though 讀一次，意思完全一樣。這裡要特別提醒一個從國中就常錯到現在的地方：中文說「雖然……但是……」兩個都要出現，英文只能留一個。Although a stye can look unpleasant, but it is harmless. 是錯的，but 必須拿掉。原因不是「一句話只能有一個連接詞」——一句話當然可以有好幾個；而是 although 和 but 綁子句的方式不同：although 讓一個子句附屬於另一個（從屬連接詞），but 是把兩個地位相等的子句並排（對等連接詞），同一對子句不可能既一主一從、又兩兩對等（劍橋 English Grammar Today）。記法很簡單：一句話可以有好幾個連接詞，但同一對子句只能被綁一次。所以 although 配得上 still、nevertheless 這種副詞（Although it rained, we still enjoyed it. 雖然下雨，我們還是玩得很開心），就是配不上 but。「因為……所以……」錯在同一個地方：Because it rained, so we stayed home. 的 so 一樣要拿掉。
As（當……的時候／因為）表時間或原因，代進去會變成「因為看起來不舒服，所以無害」，前後不通。If（如果）是條件，但針眼看起來不舒服是既成事實，不是假設。Unless（除非）等於 if...not，代進去變成「除非看起來不舒服，否則無害」，語意完全走樣。同一個 Although 在 96 年第 19 格也考過，出題方式一模一樣：前後句一正一負就挑讓步連接詞，先判方向再挑詞。
although（雖然）、even though（即使、雖然）、though（雖然）、in spite of（儘管，後面接名詞）、despite（儘管，後面接名詞）、unless（除非）、nevertheless（然而、儘管如此）、heal on their own（自行痊癒）、speed up（加快）。
You begin to notice a bit of pain on your eyelid each time you blink. You 16 the mirror to find a tiny red spot on the base of your lower lashes. These 17 are probably the beginning of an eye stye. An eye stye is a small bump, resembling a pimple, that develops when an oil gland at the edge of an eyelid becomes infected by bacteria. These bacteria are found in the nose and are easily 18 to the eye when you rub your nose, then your eye. Pus will build up in the center of the stye, causing a yellowish spot. Usually a stye is accompanied by a swollen eye.
19 a stye can look unpleasant at times, it is usually harmless and doesn't cause vision problems. Most styes heal on their own within a few days. You might speed up healing time by gently pressing a warm washcloth 20 your eyelid for 10 minutes, 3 or 4 times a day. Make sure you don't squeeze or pop a stye like you would a pimple. Doing so may cause a severe eye infection.