HELP what does *k1, slide off the needle yo* mean?

[bridgeodn]

The pattern is a diagonal knit scarf....cute, fun and ... ait of a difficulty
the row before calls for
*k1, yo*
next row
*k1,slide off the needle yo*

These are the 2nd and 3rd rows in a lace pattern of five rows.. to complicate mattters further there are a derease and increase at the beg and end of every other row.. to form the diagonal shape of the scarf..
Please help! Thanks to any and everyone[font="Arial"][SIZE="5
Bridge
The pattern is for the Balck and White Diagonal Striped Scarf from www.mylittlecitygirl.com
the stiches I need help with are from the Lace Pattern portion... found at the top of page 3..Rows 3 and four

[suzeeq]

On the 2nd row you drop the yo from the previous row off the needle.