What is the main clause of the sentence Most of the juniors will be going on the field trip to the capitol?

The main clause of the sentence "Most of the juniors will be going on the field trip to the capitol" is "Most of the juniors will be going." This part expresses the primary action and the subject of the sentence, indicating that a majority of the juniors are participating in the planned activity. The phrase "on the field trip to the capitol" serves as additional information about where they will be going.