Write routinely over extended time frames (time for research, reflection, and revision) and shorter time frames (a single sitting or a day or two) for a range of discipline-specific tasks, purposes, and audiences.

This standard is an exact replica of the comparable standard for the fourth grade—guess someone got lazy over at Common Core HQ. 

Jokes aside, this standard focuses on the development of a broad array of writing skills, to be employed both in long and short-term contexts, which will help your students better focus their writing to serve specific purposes. And you can take it up a notch from the fourth grade workload.