为什么：That( )her ring.It( )his ring.中的两个括号要填isn't和is?

为什么：That( )her ring.It( )his ring.中的两个括号要填isn't和is? It isn‘t（ ）key,it is（ ）gold ring （填 a 或 an） what’s that?it‘s is that your ring?( )that's his ring? 补全对话,每空一词A:Excuse me,is that your ring.B:No,it isn't.It's Bi Is that a ring I've bought a gold ring .Here it is .He _____ for his wife t this is her key ring Is that his ring () the lost and found That is (a white ring)?对括号部分提问 It is very ______ that she will ring me tonight. 单项选择（ ）21.It isn’t ______ ring.It’s ________ eraser.A.an,an ring () her finger中间填什么英语单词