i found a set of keys and an english book in thelibrary ,who什么them?

Do you found your a set of key? 还有I have a set of (key). 改错 I have a set of key. I found a set of（ ）选择 A.key B.keys C.tI found a set of（ ）选择A.key B.keys C.two keys D.a key a set of ____(key). Sam found a set of -----(key)in front of his house I found a set of______(key)横线上应该填什么呀? 补全单词I found a set of k____. I have two __ .A.set of keys B.set of key C.sets of keys D.sets of I lost a set of keys.But last i found( ).填什么 Sam found a set of -----(key)in front of his house用括号内所给名词的适当形式填空． i found a set of keys and an english book in thelibrary ,who什么them? There is ( ) A.key B.a set of key C a set of keys D.keys 选哪个?为什么 是a set of keys还是a set of key?哪个正确? 那么a set of key 中“key一定要加s吗 Is that a set of key,key要不要加s? )I found a set my heart racing boy Look,____ is in the“lost and found” box.看不懂,貌似没有正确答案.要有理由A.some keys B.a set of keys C.two baseballs D.a key and a baseball貌似没有正确答案……