This service is available seven days a week during normal operating hours. 19 Happy Puppy is a relatively new service, we benefit from more than 20 years of experience in breeding and caring for dogs.
答案：(A) Although
語意轉折：「雖然 Happy Puppy 是相對較新的服務，我們卻受益於……多年經驗」，Although（雖然）符合這個讓步轉折；Because（因為）、Once（一旦）、Until（直到）都不合。
Because 通常是這一題最多人選的答案，因為「我們受益於二十多年的養狗經驗」聽起來就是一句好話，好話前面擺個「因為」讀起來很順。真正的問題是你可能沒看出來這兩個子句是對立的：a relatively new service（店是相對新開的）對 more than 20 years of experience（二十多年的經驗）—— 店新、人卻不新，這是一組刻意寫出來的矛盾。這個矛盾一旦沒讀出來，四個連接詞填進去都像可以，只好用語感猜。
先把兩個子句的意思各量一次：子句一是「Happy Puppy 是相對新的服務」，子句二是「我們有二十多年的經驗」。甲成立、乙照樣成立，而且乙聽起來和甲相衝 —— 這種關係就是讓步，英文用 Although。驗算方式很簡單：把它改寫成國中最熟的 but 句型 —— Happy Puppy is a relatively new service, but we benefit from more than 20 years of experience.（Happy Puppy 是相對新的服務，但我們有二十多年的經驗。）語意通，代表讓步關係成立。這裡順便把這條規則複習一次：中文可以說「雖然……但是……」，英文的 although 和 but 只能留一個，不可以同時出現。另外，同一份考卷的第 23 題答案是 If（條件），而 Though 是那一題的誘答選項；本題答案是 Although（讓步），If 在這裡也填不進去。兩題正好把「讓步」和「條件」拆開來各考一次，對照著看最清楚。
Because（因為）：填進去變成「因為 Happy Puppy 是新服務，所以我們有二十多年經驗」，新開的店推不出二十年的資歷，因果接不上，反過來也接不上。Once（一旦、一……就）：劍橋 English Grammar Today 說明 once 引導的子句指的是一個完成的事件或動作，主要子句才接著發生；is a relatively new service 是一個狀態，不是可以「完成」的事件，語意在這一步就卡住了。Until（直到）：until 標的是某件事持續到什麼時候為止，主要子句得是一個會被終止的動作；we benefit from... 並沒有要在某個時間點停下來。
a relatively new service（相對新的服務）、benefit from（從……受益）、more than 20 years of experience（二十多年的經驗）、care for（照顧）、once in a while（偶爾）、not … until（直到……才）。其中 not … until 這一組考過 4 個年度，88 年第 39 題 →、90 年第 24 題 →、98 年第 21 題 →都出現過。
All dogs deserve to look and feel their best. After a spa treatment at Happy Puppy, dogs come home 16 pampered and relaxed. At Happy Puppy, your dog can enjoy a half day of care and then be taken to the salon at naptime. Here all the dogs are given a bath using professional shampoo and conditioners in a massaging tub. Their relaxing bath will be 17 a full fluff dry and brush-out. When you arrive for pick-up, your dog will be well-exercised and beautiful.
You can also bring your dog to Happy Puppy and wash it yourself. We supply everything, 18 waist-high tubs, shampoo, and towels. This service is available seven days a week during normal operating hours.
19 Happy Puppy is a relatively new service, we benefit from more than 20 years of experience in breeding and caring for dogs. We are completely 20 to helping dogs enjoy a full and active life. Our well-trained staff will provide the best possible service for you and your dog.