The following is one of the items. 21 a student who is never on time, there is the new Projection Alarm Clock.
答案：(D) For
【句型】For + 對象，表示「對於……而言」，For a student who is never on time＝「對於一個總是遲到的學生而言」；Once（一旦）、Like（像）、Just（只是）都不合這個語意。
本題大考中心未公布逐題答對率，以下不談數據，只談觀念。
For 在你腦中大概第一個是「因為」，第二個是「為了」，很少想到它可以直接帶出一個對象、意思是「對……而言」。而 Like（像）擺進去唸起來也不算突兀，於是就在這兩個之間猶豫。
先看空格後面接的是什麼：a student who is never on time 是一個名詞片語（一個總是遲到的學子），不是子句。所以空格要的是能直接接名詞的字。Once 是連接詞，後面要接完整子句，先出局；Just 是副詞，接不出「Just a student..., there is...」這樣的結構。剩下 Like 與 For，用語意分：整段的脈絡是在為不同的人推薦禮物，這一句要說的是「對某一種人來說，有這樣一款產品」，是把產品對應到適用的對象，不是拿學子來打比方。For 加人＝「對……而言、給……用的」，正是這個意思。順便對照著記：91 年第 24 題也考 For，但那個 For 是「因為」的用法，它引出的是前一句的理由，位置只能在後面；本題的 For 是介系詞「對……而言」，放句首完全正常。同一個字兩種身分，看後面接的是名詞還是子句就分得出來。
Like（像）：用來打比方，會變成「像一個總是遲到的學子一樣，有一款新的投影鬧鐘」，把鬧鐘拿去跟學子相比，語意不通。Once（一旦、一……就）：連接詞，後面要接完整的子句。Just（只是、剛好）：副詞，沒有帶出名詞片語再接主要子句的用法。
For sb, there is …（對某人來說，有……）、on time（準時）、in time（及時）、be never on time（總是不準時）、be late for school（上學遲到）、be suitable for（適合）。
At times, it seems like there are not many things that we can give a student who has everything. But 16 that Christmas is just a few weeks away, 17 is a gift idea. Those who have an inclination for crazy technological advances aren't hard 18. One simple way is a few new items that might 19 life more enjoyable. They don't look too revolutionary, but you'd be surprised 20 they are capable of. The following is one of the items.
21 a student who is never on time, there is the new Projection Alarm Clock. Many ordinary clocks are hard to read early in the morning, deceiving students of the correct time, 22 causing them to be late for school. Through a projector, this attractive radio-alarm-clock is able to display the time onto a wall, ceiling, or anywhere 23. The benefits include an easier visibility of the time, and an alarm that gets increasingly louder 24 turned off. It won't magically transport a student to school on time every day, but it just might make 25 a little easier.