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A recent study compared two ways to protect memory after sleep deprivation: aerobic exercise and a nap. Researchers wanted to know whether a short period of exercise really provides some of the same cognitive benefit as a nap. Going without sleep makes it harder to concentrate and learn new information, and for people who work overnight, enough rest may not always be possible.

The study kept 54 healthy adults, ages 18 to 35, awake for 30 hours. They were then randomly put into one of three groups. One did 20 minutes of hard cycling at 80% of their maximum heart rate. Another had a 90-minute opportunity to nap. The control group did not exercise or nap. Afterward, the participants viewed 150 images while researchers recorded their brain activity. Three days later, they saw the original images mixed with new ones and were asked which they remembered.

Participants who exercised correctly recognized 56% of the images, compared with 57% among those who napped and 46% in the control group. Both groups performed much better than the control group. There was no significant difference between exercise and napping. Interestingly, those who napped reported feeling much less tired afterward, while those who exercised reported similar levels of fatigue to the control group, yet still did better on the memory test.

Sleep loss interferes with the brain’s ability to store new information, so the processes needed to form memories become less efficient. The recordings suggest that exercise helped reduce some of these effects. The nap worked differently. It gave the brain some of the sleep it was demanding, while exercise helped the brain work more effectively even though it had still lost sleep.

Sleep serves essential functions throughout the body, including supporting many aspects of brain function. In safety-related jobs, however, a short period of exercise could offer another way to protect memory when a nap is not possible. But it does not make it safe to drive after severe sleep loss.

1.1. What did the researchers mainly want to compare?

A Sleep loss and driving safety.

B Exercise and napping benefits.

C Brain activity and image recall.

D Overnight work and rest time.

解析：选B。B细节理解题。文章首句明确说“A recent study compared two ways to protect memory after sleep deprivation: aerobic exercise and a nap”，即研究主要比较有氧运动和午睡这两种在睡眠剥夺后保护记忆的方式，并进一步说明研究者想知道短时运动是否能提供与午睡相同的认知益处，所以选B“Exercise and napping benefits”。A“睡眠损失与驾驶安全”只在最后一段作为提醒出现，不是研究主要比较对象；C“大脑活动与图像回忆”是实验中的记录和测试内容，不是研究目的；D“夜班工作与休息时间”只是背景信息，均不选。故选B。

2.2. What does the finding about the exercise group suggest?

A Exercise helps memory despite tiredness.

B Tired people always remember less.

C Exercise removes all sleep pressure.

D Cycling is easier than napping.

解析：选A。A推理判断题。运动组正确识别率为56%，明显高于控制组的46%，而且文中说运动组“reported similar levels of fatigue as the control group, yet still did better on the memory test”，说明尽管他们仍然感到疲劳，记忆表现却更好，因此可推出A“Exercise helps memory despite tiredness”。B“疲劳的人总是记得更少”中的always过于绝对，且与运动组表现不符；C“运动消除所有睡眠压力”中的all过度推断，文中只说exercise helped reduce some of these effects；D“骑行比午睡更容易”文中没有比较两者难度，均不选。故选A。

3.3.The underlined phrase “interferes with” in Paragraph 4 is closest in meaning to “______”.

A transforms

B improves

C creates

D weakens

解析：选D。D词义猜测题。第四段说“Sleep loss interferes with the brain’s ability to store new information, so the processes needed to form memories become less efficient”，后半句“形成记忆所需过程变得不那么有效”说明睡眠损失是“干扰、削弱”大脑储存新信息的能力，因此interferes with最接近weaken“削弱”。A“transform改变”、B“improve改善”、C“create创造”都与后文“less efficient”的逻辑不符，均不选。故选D。

4.4. What does the author mainly suggest in the last paragraph?

A Exercise helps when naps are impossible.

B Naps always work better than exercise.

C Tired drivers can exercise safely.

D Sleep loss harms only memory.

解析：选A。A推理判断题。最后一段指出，在安全相关的工作中，当无法午睡时，短时运动可以成为保护记忆的另一种方式，但紧接着警告这并不能使人在严重睡眠不足后安全驾驶。因此作者主要建议是A“当无法午睡时，运动有帮助”。B“午睡总是比运动更好”中的always过于绝对，且前文说两者无显著差异；C“疲劳司机可以安全运动”偷换概念，最后一句明确说不能因此安全驾驶；D“睡眠损失只损害记忆”中的only与“Sleep serves essential functions throughout the body”矛盾，均不选。故选A。