二次函数y=x2+6kx+9k2(k>0)图象的顶点在[ ] A．x轴的负半轴上 发布时间：2017-05-11 18:32 │ 来源：www.tikuol.com 题型：选择题 问题： 二次函数y=x2+6kx+9k2(k>0)图象的顶点在 [ ]A．x轴的负半轴上 B．x轴的正半轴上 C．y轴的负半轴上 D．y轴的正半轴上
题型：选择题 完形填空。 Bill Gates 1 on October 28th, 1955. He 2 in Seattle, Washington. His favorite subjects at schoolwere science and math. 3 he was 13 years old, Bill started to play with computers. Computers at that time 4 very large, but he was interested 5 them. He 6 lots of time doing unusual things with computers. In the end, he and some of his friends worked out a software program (软件程序) with an old computer. He 7 it for ＄4,200 dollars. In 1973, Bill 8 Harvard University (哈佛大学). He left there in the third year to work for a company called Microsoft. In 1975 Bill began his company 9 his friend Paul Allen. They developed software for personal computers. They improved (改进) the software to make it 10 forpeople to use computers. ( )1. A. is born ( )2. A. grow ( )3. A. At ( )4. A. is ( )5. A. at ( )6. A. took ( )7. A. sell ( )8. A. went ( )9. A. and ( )10. A. easy B. was born B. grew B. Until B. are B. in B. put B. sale B. went to B. with B. easier C. did born C. grew up C. When C. was C. on C. paid C. sold C. want C. for C. difficult D. born D. has grew up D. At the moment D. were D. for D. spent D. bought D. wanted D. by D. more difficult 查看答案