PHRASAL VERBS
work something in try to include something.
get worked up gradually come into a state of intense excitement, anger, or anxiety. have one’s work cut out be faced with a hard or lengthy task. in the works being planned, worked on, or produced. work in try to include (something). work off reduce or eliminate by activity. work on/upon exert influence on. work out 1 solve or be capable of being solved. 2 develop in a good or specified way. 3 plan in detail. 4 understand the character of. 5 engage in vigorous physical exercise. work out at be calculated at. work over informal beat up. work one’s passage pay for one’s journey on a ship with work instead of money. work to rule chiefly Brit. follow official working rules and hours exactly in order to reduce output and efficiency, as a form of industrial action. work up to proceed gradually towards (something more advanced). work up develop or improve (something) gradually. — DERIVATIVES workless adjective.
work something off
1 discharge a debt by working.
2 reduce or eliminate something by activity.
work out
1 be capable of being solved.
2 develop in a good or specified way.
3 engage in vigorous physical exercise.
work out at be calculated at.
work someone out understand someone's character.
work something out
1 solve something.
2 plan something in detail.
work someone over informal beat someone up.
work up to proceed gradually towards (something more advanced).
work someone up (often get worked up) gradually bring someone, especially oneself, to a state of intense excitement, anger, or anxiety.
work something up
1 develop or improve something gradually.
2 develop by activity or effort.
DERIVATIVES
workless adjective
Source : Oxford Dictionary
so teh answer is work on