某实验小组用小球藻进行实验，探究影响光合速率的因素。他们将一定量的小球藻浸入适宜且相
题型：问答题 案例分析题
问题：
某实验小组用小球藻进行实验，探究影响光合速率的因素。他们将一定量的小球藻浸入适宜且相同温度的培养液的试管中，以白炽台灯作为光源。移动台灯可改变光源与试管的距离；CO2浓度分别设置为0.03%和0.05%，根据实验结果绘制成曲线1、曲线2
1，2两条曲线相交于E点的原因是
题型：问答题 案例分析题
| 完形填空。 | |||
| But 1 a few of them are very 2 . English is one of these. Many, many people use it, not only in England and the U. S. A, but in other parts of the world. About 200, 000, 000 speak it as their own language. It is difficult to say how many  people are learning it as a 3 language. Many millions are 4 to do so. Is it easy or difficult to learn English? Different people may have different 5 . Have you ever 6 the ads of this kind in the newspapers or magazines? 'Learn English in six month, or your 7 back ...' 'Easy and funny? Our records and tapes 8 you master your English in a month. 9 the first day your 10 will be excellent. Just send ..." Of course, it never 11 quite like this. The only language that seems easy to learn is the mother tongue. We should 12 that we all learned our own language well when we were 13 . If we could learn English in the same way, it would not seem so difficult. 14 what a small child does. He listens to what people say. He tries what he hears. When he is using the language, talking in it, and 15 i  n it all the time, just imagine how much 16 that gets! So it is 17 to say that learning English is easy, because a good command of English 18 upon a lot of practice. And practice needs great effort and 19 much time. Good teachers, records, tapes, books, and dictionaries will 20 . But they cannot do the student's work for him. | |||
| ( )1. A. not ( )2. A. difficult ( )3. A. native ( )4. A. learning ( )5. A. questions ( )6. A. found ( )7. A. knowledge ( )8. A. make ( )9. A. From ( )10. A. spelling ( )11. A. happened ( )12. A. know ( )13. A. students ( )14. A. Imagine ( )15. A. using ( )16. A. time ( )17. A. hard ( )18. A. depends ( )19. A. uses ( )20. A. do | B. quite B. important B. foreign B. enjoying B. problems B. watched B. time B. help B. On B. grammar B. know B. remember B. children B. Mind B. thinking B. money B. easy B. tries B. takes B. work | C. only C. necessary C. useful C. trying C. ideas C. noticed C. money C. let C. Since C. English C. seemed C. understand C. babies C. Do C. trying C. language C. funny C. has C. gets C. help | D. very D. easy D. mother D. liking D. answers D. known D. English D. allow D. After D. pronunciation D. felt D. think D. grown-ups D. Think of D. practicing D. practice D. silly D. takes D. costs D. master |