what is your sister's name?记住:我(I)用 am 你(you )用 are is 跟着 he she it复数都用are
is本句主语为your sister's 是第三人称单数所以用is
is 名字是第三人称单数
isam是专门给I有的:I amis是给一个有的:有she,he,itare是在很多个上面的:有they,you
is