Answer:
Both the House and Senate are working on similar bills that need to be combined
Step-by-step explanation:
A joint sub-committee work on a bill in which "both the House and Senate are working on similar bills that need to be combined."
This is because a joint sub-committee is a committee that has members from both the Houe and Senate. They then work together on a particular subject or bills such that the outcome is combined in making a shared function.