Question

用be动词填空 his pens（）black and white that（）my brother。he（）thirteen years old。

Answer 1

His pens（are）black and white that (is) my brother.
He (is) thirteen years old。
因为pens是复数，所以用are
he是第三人称单数，所以用is

追问

填be动词
lisa and mike（）my cousins
our english tercher（）very pretty
you（）very nice
she（）my good friend
they（）in the same school
some salad（）on the table
these（）my english books

追答

1.are and前后都是主语，是两个人，所以用are
2.is our english tercher是一个人，所以用is
3.are you用are
4.is she用is
5.are they是复数
6.is salad是不可数名词
7.are these

Answer 2

are，is，is
pens为复数用are，后面两空主语是单数，用is

Answer 3

his pens（are）black and white that（is）my brother。he（is）thirteen years old。

Answer 4

lisa and mike （are）my cousins
our english teacher (is) very pretty
you (are) very nice
she (is) my good friend
they (are) in the same school
some salad (is) on the table
these (are) my english books