The children are happily jumping on the trampoline.
Pronunciation: Dee KIN-der SHPRIN-gen FRÖH-likh auf dem TRAM-po-leen.
Grammar: „springen“ is a regular verb in the present tense: ich springe, du springst, er/sie/es springt, etc.; it often takes the preposition „auf“ with dative or accusative, depending on movement.