Kittens usually begin grooming themselves when they are about four weeks old. 19 five weeks of age, kittens also begin grooming other baby cats, as well as their mom. 20 grooming among cats, called allogrooming, often continues into adulthood.
答案：(C) Mutual
語意「貓咪之間彼此理毛，稱為互相理毛」，Mutual（互相的）符合allogrooming（互相理毛）這個字的定義；Early（早期的）、Natural（自然的）、Personal（個人的）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。
這一篇一開始講的是貓「替自己」理毛，所以 Personal（個人的）看起來很合理；但這一段講的已經不是自己理自己，是彼此互相。
四個選項都是形容詞，可見這一格考的是語意，那就往前讀一句。前一句是 kittens also begin grooming other baby cats, as well as their mom（幼貓也開始替其他幼貓和媽媽理毛）——重點在 other baby cats 與 their mom，理毛的對象是別的貓，不是自己。本句是 ___ grooming among cats, called allogrooming, often continues into adulthood（貓之間的……理毛，稱為 allogrooming，常會持續到成年）。既然是彼此替對方理，就是「互相的」，填 Mutual。還有一個字本身就在提示：allogrooming 的字首 allo- 來自希臘文，意思是 other（其他的），整個字就是「替別的個體理毛」，與 mutual 的意思完全吻合。再看 among cats（在貓與貓之間）也印證了這是雙向的行為。
Personal（個人的、自己的）：方向相反，這一段講的正是替「別的貓」理毛。Early（早期的）：與時間有關，但這一句要說的是對象不是時間；而且後半句說它會持續到成年，反而不限於早期。Natural（天生的）：這一篇第一句確實提過 naturally equipped，但那是講配備，不是講「互相」這個特性。
mutual respect（互相尊重）、mutual benefit（互利）、a mutual friend（共同的朋友）、among（在……之間，三者以上）、continue into adulthood（持續到成年）、strengthen the bond（強化連結）。
When it comes to personal hygiene, cats are the best example of cleanliness. They are naturally equipped with 16 they need to groom themselves: a flexible tongue with which to lick, forepaws they moisten with saliva and use like washcloths, and teeth to dig out tougher pieces of food. 17, adult cats may spend as much as half of their waking hours grooming themselves, their relatives and friends.
Mothers begin licking their kittens 18 birth---to clean them, stimulate the release of body waste, wake them up to suck milk, and provide comfort. Kittens usually begin grooming themselves when they are about four weeks old. 19 five weeks of age, kittens also begin grooming other baby cats, as well as their mom.
20 grooming among cats, called allogrooming, often continues into adulthood. Allogrooming is a social activity that serves to strengthen the bond between cats.