Have you ever stayed up late? If so, you know that not getting enough sleep can make you tried and grumpy . Not sleeping enough sleep can also make it harder to think clearly the next day. Sleep scientists have long known that getting a good night's sleep is very important. It helps kids be able to do their best during the day. A recent study shows that sleep helps improve problem-solving skills and creative(创造性的) thinking. For the study, two groups of students answered a math problem. The group that slept for eight hours solved the problem correctly more often than the group that did not get enough sleep. While you sleep at night, your brain is busy doing its 'homework'. It sorts out(整理) all the information that you get in the day. Getting enough sleep each night can improve your thinking ability. That will surely help you do your best at school. Experts say that, in return, can lead to better grades. 1. The underlined word grumpy in the first paragraph means_______. A. excited and happy B. active and creative C. impatient and angry D. bored and weak 2. Choose the best title for this passage. A. Sleep to Success B. A Recent Study C. Do Sleep Well D. The More Sleep, the Better