英语there 是there is a girl and a boy还是there are a girl and a b

应该是there is a girl and a boy.
判断的依据:第一个名词是单数,用is
如第一个名词是复数,就用are,
例:There is a box and two pencils on the table.
There are two pencils and a box on the table.
句子不同,但意思相同．