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.
答案：(B) therefore
因果關係：「許多普通時鐘在早上很難看清楚，讓學生誤判時間，因此導致他們上學遲到」，therefore（因此）符合這個因果邏輯；though（雖然，轉折）、otherwise（否則）、however（然而，轉折）都不合。
本題大考中心未公布逐題答對率，以下不談數據，只談觀念。
四個選項裡有三個帶著轉折的味道（though、otherwise、however），只有一個是因果。如果沒有先把前後兩件事的關係想清楚，很容易被「多數決」的錯覺帶走，覺得答案應該落在那三個裡面。
四個選項都是轉承語，可見這一格考的是前後兩件事的邏輯關係，那就把空格兩邊各是什麼事看清楚。前面是 deceiving students of the correct time（讓學子誤判時間），後面是 causing them to be late for school（導致他們上學遲到）。誤判時間在前、遲到在後，前者正是後者的原因，這是順向的因果，不是轉折，therefore（因此）才是做這件事的字。結構上也可以印證：deceiving 與 causing 是兩個並列的現在分詞，補充說明前面整句話所造成的結果（劍橋 English Grammar Today 的 -ing clause 表 result），還原成 and this deceives students ..., and therefore causes them ...，兩個結果一前一後，中間的關係只能是因果。
though（雖然）：表讓步或轉折，會變成「讓學子誤判時間，雖然導致他們遲到」，兩件事本來同向，硬要轉折就講不通。however（然而）：同樣是轉折。otherwise（否則）：需要前面先有一個「如果不那樣做」的前提，本句沒有。
deceive sb（欺騙某人）、cause sb to V（導致某人……）、hard to read（不好辨讀）、as a result（因此、結果）、lead to（導致）、result in（造成）。
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.