题目

下列实验中的颜色变化,与氧化还原反应无关的是 ABCD 实验NaOH溶液滴入FeSO4溶液中石蕊溶液滴入氯水中Na2S溶液滴入AgCl浊液中热铜丝插入稀硝酸中 现象产生白色沉淀,随后变为红褐色溶液变红,随后迅速褪色沉淀由白色逐渐变为黑色产生无色气体,随后变为红棕色 答案:CDirections: Read the following passage.Answer the questions according to the informationgiven in the passage.Why should you keep exercising even when cold temperatures make you want to hide under the covers? With the temperatures dropping at this time of year, many of us tend to hibernate (冬眠) inside our homes. But, hibernating is for bears. As humans it’s important to stay active through all four seasons. Yet, a poll of 5,000 people found that 30 percent get no exercise at all during the winter months.Just because it is cold outside it is no excuse not to exercise. There are many exercise choices one can choose to take part in regardless of the cold weather. Depending on your location and likes, you can choose to exercise inside or outside.All that is required for winter-time exercise is some planning and the following of some safety tips. If you prefer to exercise outside, keep the following tips in mind.Get warm first. A proper warm-up is critical. Cold temperatures can make your muscles tight and therefore they are easier to be injured. So, it’s important to get them warm-up before intense (激烈的) physical activity. No sweat. Don’t assume that you have to sweat in order to get a good workout. You should avoid sweating that causes the clothing layer closest to your skin to get wet and cause you to be cold.Don’t undress when you get inside. While you may want to immediately remove your layers when returning inside, you should give your body time to adjust.Drink up. It’s just as important to stay hydrated (含水的) when exercising in winter as it is in summer, even though you might not feel as thirsty.Be seen. If possible, it’s best to exercise outdoors during daylight areas. If you exercise outdoors when it is dark, wear reflective (反光的) materials to ensure that you can be seen.By staying fit during winter, you’ll be able to avoid gaining weight and losing strength caused from inactivity.【小题1】 Why is it important to get your muscles warmed-up before intense physical activity? (no more than 16 words)_____________________________________________________________________________【小题2】What are needed for exercising in winter? (no more than 6 words)_____________________________________________________________________________【小题3】What are the advantages of staying fit during winter? (no more than 9 words)_____________________________________________________________________________【小题4】What’s the main idea of the text? (no more than 4 words)_____________________________________________________________________________
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