Source: http://www.sing365.com

Passing By
   ------Beach Boys

instrumental


note: This song has lyrics:
"While walking down the avenue
I stopped to have a look at you
And then I saw/You're just passing by"

but Brian decided not to use them.
I don't know if these lyrics were ever recorded.
You can sing these lyrics to the part Brian is humming.

source: http://www.cabinessence.com/brian/tracks/files/p/passing_by.shtml