1. Discuss the differences in environment, such as controlled conditions in a pool versus natural conditions in the sea. 2. Mention differences in water conditions, like saltwater versus chlorinated water, and the presence of waves or currents in the sea. 3. Consider safety aspects, such as lifeguards in pools and potential hazards in the sea.

1. 讨论环境的差异，例如游泳池中的受控条件与海洋中的自然条件。 2. 提到水质的差异，如盐水与氯化水，以及海洋中波浪或水流的存在。 3. 考虑安全方面，例如游泳池中的救生员与海洋中的潜在危险。