下列方程中是关于x的一元二次方程的是（ ） A．3x2-2xy-5y2=0 B．ax 发布时间：2017-04-20 15:17 │ 来源：www.tikuol.com 题型：选择题 问题： 下列方程中是关于x的一元二次方程的是（ ）A．3x2-2xy-5y2=0B．ax2+bx+c=0C．x2+1x2=0D．（x-1）（ x+2）=1
题型：选择题 完形填空。 Jack is 1 American boy. He is one of the best students in his class, he is 2 his lessons,and he can speak 3 Chinese. But Jack enjoys 4 best. One day, he 5 his homework, instead (而是/相反) he went to a swimming pool. When he was swimming, suddenly (突然) he heard a scream (尖叫). "Excuse me,what can I do 6 you,sir?", he asked,"Yes, I would like someone 7 me how to swim?" The man answered. "Really?You can't swim?Ok, let me 8 you., I'm sure you can swim very well soon."After a while (一会儿), the man could swim. Jack said to him,"Look, you are a 9 man.""Thank you"" 10 ". ( )1. A. a ( )2. A. bad in ( )3. A. little ( )4. A. swim ( )5. A. doesn’t ( )6. A. for ( )7. A. teach ( )8. A. help ( )9. A. clever ( )10. A. That’s right B. an B. good at B. a little B. swims B. doesn’t B. to B. teaches B. to help B. friendly B. welcome C. x C. well in C. a few C. swimming C. didn’t C. of C. to teach C. helped C. funny C. That’s all right D. the D. hard at D. a bit D. to swim D. didn’t do D. with D. teaching D. helping D. polite D. Ok 查看答案