问题
选择题
| 如图所示为一磁流体发电机示意图，A、B是平行正对的金属板，等离子体（电离的气体，由自由电子和阳离子构成，整体呈电中性）从左侧进入，在t时间内有n个自由电子落在B板上，则关于R中的电流大小及方向判断正确的是（ ） A．I= B．I= C．I= D．I=  |
答案
答案：A
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| 如图所示为一磁流体发电机示意图，A、B是平行正对的金属板，等离子体（电离的气体，由自由电子和阳离子构成，整体呈电中性）从左侧进入，在t时间内有n个自由电子落在B板上，则关于R中的电流大小及方向判断正确的是（ ） A．I= B．I= C．I= D．I= |
答案：A
| 完形填空。 | |||
| A professor (教授) told his students to go into the city slums (贫民窟) to study the life of 200 boys. He asked them to 1 reports about each boy's life and future. Every one of the students wrote, "He doesn't have any hope. " Twenty-five years 2 , another professor read about the earlier study. He told his students to 3 what had happened to the boys. They tried very hard and found that 176 of the boys had become successful 4 doctors, teachers and scientists. The professor was very 5 and decided to study further. Luckily, all the men were living near the place and was able to ask each one,"What made you 6 ?"Each one answered,'There was a teacher. " The teacher was 7 living there so the professor found her and asked the old woman 8 she had used to pull those boys 9 the slum, and change them into successful people. The teacher's 10 began to shine and said with a sweet smile. "It's really very easy.I loved those boys. " | |||
| ( )1. A. read ( )2. A. later ( )3. A. search ( )4. A. for ( )5. A. glad ( )6. A. wonderful ( )7. A. already ( )8. A. what ( )9. A. out ( )10. A. face | B. study B. after B. find out B. With B. angry B. successful B. yet B. who B. into B. eyes | C. write C. ago C. look for C. as C. surprised C. rich C. even C. which C. away C. hair | D. take D. before D. see D. like D. worried D. popular D. still D. when D. out of D. mouth |