What is the prepostional phrase marcy plans to select a worthy charity and offer to help with fund- raising events?

Your sentence, "Marcy plans to select a worthy charity and offer to help with fund- raising events" has two prepositional phrases, I believe. First, "to select a worthy charity" and second "to help with fund- raising events". However, the verb phrase "offer" is incorrect; it does not match the verb tense "plans". It is also unclear who is doing the offer--it should refer back to "a worthy charity" with the way the sentence is Worded, but I think you want it to refer to Marcy. For example: Marcy plans to select a worthy charity and she has offered to help with fund- raising events. Or and she offers...