根据要求写出下列词的相应形式。sister（对应词）father（对应词）that（复数）this（复数）R（同音词）

sister- brother
father- mother
写出下列单词的复数形式。this- these
that -those
,key,- keys
is - are
friend,-friends
she-they
isn't - aren't
family.- families
用am,are,is填空.These ( are )his brothers.
That ( is )Paul。He( is )my friend.
Those ( are )my parents.