Let p, q, and r denote the following propositions: p denotes "there is a flood warning" q denotes "it rains every day for a week" r denotes "class is canceled" Using p, q, and r construct compound propositions which represent the following English sentences: (1) It rains every day for a week and there is a flood warning but class is not canceled. (2) Class is canceled if it rains every day for a week. (3) It rains every day for a week if and only if there is a flood warning