Split and simplify the following sentence while retaining its full meaning: Whereas Community law imposes on the Commission and the Member States an obligation to check that Community budget resources are used for their intended purpose; whereas there is a need for common rules to supplement existing provisions.
 Simplified version:
Under Community law , the Commission and the Member States are obliged to check that the Community's budget is being used for the intended purpose . Common rules are to be provided to supplement the applicable regulations .