重度消瘦的诊断标准是（）
A.其体重低于同年龄、同性别参照人群的均数减2个标准差，但高于或等于均数减3个标准差
B.其体重低于均数减3个标准差
C.其体重低于同性别，同身高参照人群值的均数减2个标准差，但高于或等于均数减3个标准差。
D.其体重低于同性别同身高参照人群值的均数减3个标准差
E.体重低于同年龄同性别参照人群值的均数减30％
参考答案：D
| 根据短文内容，从下框的A-F选项中选出能概括每一段主题的最佳选项。选项中有一项为多余选项。 | |||
Science is an amazing subject, but it's difficult to capture the true magic of science and contain it in a book. For young learners, textbook science often looks like a lot of big, confusing terms that have to be memorized. That is why sometimes children think that science is dry, boring and difficult. Textbooks can't help them discover how exciting science really is. So find some other ways to help kids to develop a love of science. 2_____ Instead of just reading from a book about the water cycle, air pressure, chemical changes, sound waves, fingerprints, etc., let students experience these things instead. It's much more memorable for them to discover a principle or fact about science on their own than it is to simply be told about it. There are great resources online that include complete lesson plans for hundreds of activities. Afterwards, a brief discussion can bring the principal points home to children. In addition, an explanation of any unfamiliar terms at this point will make a lot more sense. 3_____ Science is all around. Taking time to look at the world and to discuss what is seen, encourages scientific observation and a love of learning. Look at changing seasons, weather events, plants, pets, insects, the stars and virtually everything else as an opportunity to help students learn more about science. 4_____ Real scientists record their findings. Encourage young scientists to draw pictures and write about what they see and do. Science isn't an isolated subject. It involves reasoning, writing, math, history, art, and more. A journal gives students a place to record the things about science that interest them most. 5_____ Cooking is filled with chemical reactions. Teach students about what happens when carbon dioxide bubbles form in dough. Help them to understand mixtures by making a salad, solvents by mixing up powdered drink mixes, colloids by making gelatin, evaporation and cloud formation by observing a boiling tea kettle. Crystals can be observed (and grown) with salt and sugar. Liquids can be changed to solids in a freezer. The list is almost endless. | |||
