講解答案:
D本題問“為什么寵物狗喜歡為主人表演技能?”根據第三段中Training is also an easy way to establish the social rank order... You can teach your dog its subordinate role by teaching it to show submission to you. Most dogs love performing tricks for you to pleasantly accept that you are in charge.(訓練也是建立社會等級的方法。你可以通過教狗表示服從你,來教它扮演從屬的角色。 大多數的狗都喜歡為你表演技能以此來表示樂意接受你的主宰地位。)所以被馴服的寵物狗喜歡 為人表演技能的原因是to show their willingness to obey。所以D是正確答案。
vt. 使富足,使肥沃,添加元素