■ Because they are always swimming, tunas simply have to open their mouths and water is forced in and over their gills.■ Accordingly, they have lost most of the muscles that other fishes use to suck in water and push it past the gills.■ In fact, tunas must swim to breathe.■They must also keep swimming to keep from sinking, since most have largely or completely lost the swim bladder, the gas-filled sac that helps most other fish remain buoyant.
Look at the four squares [■] that indicate where the following sentence could be added to the passage.
Consequently, tunas do not need to suck in water.
Where would the sentence best fit?
Click on a square [■] to add the sentence to the passage.
解题思路：此题的带插入句子当中并没有代词，这时我们可以根据关联词来解答题目。带插入句子当中的Consequently(结果是...)可以给我们暗示。带插入句子的含义为：结果是，tunas(金枪鱼)不需要吸水。那么该句子的前方应该在陈述关于导致金枪鱼不需要吸水的内容。此题正确答案选C。在第三个空格之前的这句话：...they have lost most of the muscles that other fishes use to suck in water and push it past the gills. (金枪鱼失去了像其他鱼类的嘴里所拥有的一块肌肉，这块肌肉用于吸水和从腮里排水。)既然已经失去了这块用来吸水的肌肉，那么自然紧接着陈述，其结果，即金枪鱼不再需要吸水。
V 细节题 Factual Information questions
The muscles of these fishes and the mechanism that maintains a warm body temperature are also highly efficient. A bluefin tuna in water of 7°C (45°F) can maintain a core temperature of over25°C (77°F). This warm body temperature may help not only the muscles to work better, but also the brain and the eyes. The billfishes have gone one step further. They have evolved special "heaters" of modified muscle tissue that warm the eyes and brain, maintaining peak performance of these critical organs.
10. According to paragraph 9, which of the following is true of bluefin tunas?
○Their eyes and brain are more efficient than those of any other fish.
○Their body temperature can