A commemorative speech has to do with celebrating something or someone. If you want to pay tribute to someone (and there isn't a specific topic you have to talk about), you should talk about someone important to you, someone whom you love and who inspires you - it could be a family member or a friend, or someone you look up to.
Is after the underlined word? If so, it'd be a preposition. It's followed by a noun.
Since Gatsy first met Daisy, five years have passed because he has been away at war and then involved in business to make the money he believes he needs to win Daisy's love. Not until he is rich does he arrive at West Egg. In the meantime Daisy has married Tom Buchanan and had a daughter, Pammie. Gatsby also threw huge parties hoping that Daisy would one day stumble across the party. He even bought a house across from hers.
