[解析]
(1)D.推理判断题。根据后文And about 40% of fish species are in fresh water.(大约40%的鱼类生活在淡水中。)以及本段小标题Where fish live(鱼生活在哪里)可知,大多数鱼是生活在盐水中的。D选项Most of the world's fish live in salt water.(世界上大多数的鱼生活在盐水中。)符合语境,故选D。
(2)G.推理判断题。根据前文Fish have organs that tell them what is happening in the water around them.(鱼的器官告诉它们周围的水里发生了什么。)可知,本段讲述的是与鱼的感官有关。G选项Fish can also feel water movements,thus feeling the dangers that approach them.(鱼也能感觉到水的运动,从而感觉到接近它们的危险。)符合语境,故选G。
(3)E.根推理判断题。据前文Fish are cold﹣blooded.(鱼是冷血动物。)可知,本句讲述的是鱼的体温。E选项Their body temperature changes with their surroundings.(他们的体温随着周围环境的变化而变化。)符合语境,故选E。
(4)B.段落大意题。根据下文Millions of people all over the world depend on fish as a main form of nutrition.(全世界有数百万人以鱼为主要营养来源。)可知,本段是讲述鱼的重要性。B选项The importance of fish(鱼的重要性)符合语境,故选B。
(5)C.推理判断题。根据下文They eat other sea animals and are eaten by other sea creatures,thus keeping up the balance of nature.(它们吃其他海洋动物,也被其他海洋生物吃,因此保持了自然界的平衡。)可知,鱼是食物链的一部分。C选项Fish are a part of the food chain.(鱼是食物链的一部分。)符合语境,故选C。