my brother and i. peter's and henry's. jack's. mike and joan. David's. a new computer. mary and i

my brother and i 代 we

peter's and henry's theirs

jack's his

mike and joan they

David's his

mary and i we

a new computer it

my brother and i. ----- we
peter's and henry's.------their's
jack's.-----his
mike and joan.______they
David's.------his
a new computer.---------it
mary and i-----------we

my brother and i:we/us
peter's and henry's:their/theirs
jack's:his
mike and joan:they
David's:his
a new computer:it
mary and i:we/us

不知道对不对。嘻嘻。

my brother and I代we

peter's and henry's代theirs 【名词性物主代词】或their【形容词词性物主代词】

jack's代his

mike and joan代they或these

David's代his【第一种是名词性物主代词，第二种是形容词词性物主代词】

a new computer代it

mary and I代we