NEW TOEFL Reading Practice Test #3

Explanation:

The passage explicitly states: "For decades, scientists believed that sleep was simply a passive state of rest, a time when the body and brain were inactive. Modern research has dramatically revised this understanding. Sleep is now recognized as an active process involving complex neurological activity." This directly describes the change from viewing sleep as passive to understanding it as active, supporting option C. Option A contradicts the passage, which emphasizes sleep's important functions. Option B is also contradictory; modern research has revealed sleep to be more important, not less. Option D introduces a specific duration (eight hours) that is not mentioned anywhere in the passage.

Explanation:

The passage describes REM sleep as a stage "during which the brain becomes highly active, similar to waking states, though the body remains largely paralyzed. Most dreaming occurs during REM sleep." This matches option B perfectly. Option A describes what happens during deep sleep, not REM sleep. The passage states: "During deep sleep, the body repairs tissues, builds muscle, and strengthens the immune system." Option C also describes deep sleep, which is "characterized by very slow brain waves." Option D, like option A, refers to deep sleep functions. The question specifically asks about REM sleep, requiring careful attention to which stage the passage associates with which characteristics.

Explanation:

The passage discusses the many vital functions of sleep including tissue repair, immune function, memory consolidation, and the serious health consequences of sleep deprivation. The final sentence states: "Despite spending roughly one-third of our lives asleep, we are only beginning to fully understand why sleep is so indispensable." In this context, indispensable means absolutely necessary or essential, given all the critical functions described. Option A (mysterious) relates to our incomplete understanding, but the word indispensable itself means necessary, not mysterious. Option C (complicated) might describe sleep's processes but doesn't capture the meaning of indispensable. Option D (unusual) is incorrect because the passage notes we spend one-third of our lives sleeping, making it common, not unusual.

Explanation:

The passage states: "Chronic lack of sleep has been linked to increased risk of obesity, diabetes, cardiovascular disease, and even shortened lifespan." Option C is directly mentioned in this list. Options A, B, and D all describe positive outcomes that would result from adequate sleep, not consequences of sleep deprivation. The passage indicates that sleep deprivation "impairs cognitive function, emotional regulation, and physical health," which is the opposite of improving or enhancing these functions. This question requires careful attention to whether the options describe benefits of sleep or consequences of sleep deprivation.

Explanation:

The passage explicitly states: "As the night progresses, the proportion of time spent in REM sleep increases while deep sleep decreases." This directly supports option A. Option B is the opposite of what the passage states; deep sleep decreases, not increases. Option C contradicts the information about changing proportions. Option D is not supported; the passage doesn't say that light sleep disappears, only that the relative amounts of REM and deep sleep change. The passage describes sleep cycles continuing throughout the night, each containing the various stages, though in different proportions as the night progresses.