Here______ a pencil and two pens for you.
There's a pair of shoes under the bed. ______ Ben's.

Here is a pencil and two pens for you.
There is a pair of shoes under the bed. They are Ben's.

is are

is is

Here is a pencil and two pens for you.但是A pencil and two pens are for you.这是英语中的就近原则.
a pair of trousers/glasses/shoes/gloves作主语动词用单数,但是一般来说,用代词的话要用they.