This is a set( )keys用介词in,on,under,of,for

I lost a set of keys.然后是用 Is this yours?还是Are these yours? This is a set( )keys用介词in,on,under,of,for 是where is a set of keys 还是where are 回答是It‘s 还是They're是Is this a set of keys 还是 Are they a set of keys A set of keys is here划线提问A set of keys划线提问 This is my dictionary.(改为一般疑问句 set to that a of is keys room her （连词成句） That is her watchHow do you spell it?Is this your computer?No,it isn's a set of keys. this is换he/she is,a set of keys换keys可以吗?为什么a set of keys是复数,下面一句却是is this your set of keys.is不是单数用的吗?什么情况下用at?什么情况下要换第三人称形式?什么单词前面要加the?什么情况 Here is a set ____ keys横线上填什么? here is a set of keys.改为否定句 A set of keys is in it.变为一般疑问句 是there is a set of keys还是there are a set of keys?is or are A set of keys ---(be) on the table.There ---(be) a set of keys on the table.---(Are they/Is it) your set of keys? There is ( ) A.key B.a set of key C a set of keys D.keys 选哪个?为什么 You use this set of keys for a set of keys is on the sofa.(on the sofa部分提问）__a set of keys?my keys are on the desk.(on thedesk部分提问) this,yours,keys,set,is,of,the,lost,in,and,found,case（?）连词成句 a set of keys ,a set of ...意为“一串···”,那么两串钥匙怎么表示______________________.Is this his brother 变为复数形式 _____________________________I am a boy 变为复数形式 ________________________________That is an oran Here is （）?Are these yours.A.a set ofHere is （）?Are these yours.A.a set of keys B.a set of keysC.the keys D.keys填什么 ,为什么