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滴定管可倒置于滴定管架上保存，也可装满蒸馏水，在上口加盖指形管(使用中的滴定管，也可加盖指形管或纸筒以防尘埃)。( )
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涂料产品的分类是以涂料漆基中主要成膜物质为基础。( )
Task 2Directions: This task is the same as Task t. The 5 questions or unfinished statements are numbered 41 through 45. In everyday usage "hot" means "having a lot of heat". Many people think that "cold" is something completely separated from heat. But this is not true. "Cold" simply means "having little heat". Your life depends on heat. In fact, every living thing depends on it. Without heat, every living thing would be frozen to death. All living things get their heat from the sun, which provides the conditions in which life is possible. Since before the dawn of history, man has been able to make his own heat. He has been able to release the sun’s heat that is trapped in things such as wood, coal, and oil. And he has been able to use this heat. Heat has made civilization possible. With heat, man could melt metals. As man learned to use metals and fuels, industries grew. As a result, engines were invented. These are machines that change heat energy into mechanical energy. Engine can do the work of many men. Without engines industrial civilization is impossible. Yet when the first engines were built in the 17th century, men were still wondering about the nature of heat. "What is it" they asked. Not until the early years of the 19th century did they find the right answer. Your life depends on heat. The sentence means ______.
所谓质量范围就是被测物质的分子量范围。( )
Rhesus monkey, only 4 months old, has been taken from the shoulders of its mother and put into a small steel cage. Within minutes the fright in its little brown eyes softens into curiosity, and stepping carefully, the monkey makes its way across the cage. But when a man with a white hood over his head walks in and stops two feet away, the baby freezes. It pulls its body away from the cage and quietly looks the other way, appearing to ignore the man until, two minutes later, be leaves."This is a very inhibited response," says Dr. Judy Cameron, a neurobiologist and the director of the University of Pittsburgh’s primate laboratory, watching the monkey through an opening in a curtain. "Obviously, the intruder caused this animal a great deal of anxiety."More important, for Dr. Cameron’s purposes, the baby monkey can be compared to a highly anxious or depressed human child. Now researchers are putting a spotlight on teenage depression, hoping that by learning how the disorder takes root, they can find ways to keep it from growing into a weak condition and lifelong problem for 9.5 percent of adults.The monkey studies, it is hoped, will add to the effort to make clear which aspects of brain function are involved in adolescent depression. In monkeys, depression is difficult to diagnose because, obviously, the animals cannot talk about feelings. Anxiety, though, is fairly easy to measure by observing behavior."Now, we can do all sorts of studies with the anxious monkeys that are harder to do in humans," Dr. Cameron said. "We can observe their behavior every day. We can take blood samples and look at their hormones. We can assess how they respond to stress. We can ask what’s different about their brains. And ultimately, we can search for genes that may explain people’s anxiety." How much percent of adults can be kept from growing into a weak condition and lifelong problem if researchers learn how the disorder takes root
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