Work in knitting instructions always means Knit (OR purl) as makes sense..
Work Even --in stocking knit this mean knit one row, purl the other,
................--in garter it means knit every row
-------------in all cases, it means NO INCREASES OR DECREASES
Work in Ribbing means follow the ribbing pattern.. (which can be K1, P1, or k2, P2, or even expressed as 1X 1, or 2 X 2 )
Ccontinue to work in pattern, and at the same time, means continue the pattern (which can be complicated because at the same time indicates you are about to do something (like armhole or neck shaping) that will interfer with the pattern!)
if you have a pattern (ribbing say, in an all over ribbed sweater) that then needs to be decreased, and up until now, you've started each right side row with K2, (p2, k2..) and now they directions say "bind off 6 stitches at beginning of the row".
to WORK IN PATTERN, on the next right side row (after decreasing 6, you'll start the row with P2, Not K2.. see image, the bold stitches got bound off--and now you have a new starting place for your ribbing)
does this help?