等比数列{an}的前n项和为Sn，若a1＋a2＋a3＋a4＝1，a5＋a6＋a7＋a8＝2，Sn＝15，则项数n为( ) A．12 B．1
Your suggestions on how to improve English is too general. Could you make it more______? A. specific B. particular C. special D. simp
__________ makes the school famous is __________ more than 90% of the students have been admitted to universities. A. What; because B. That;because C. That; what D. What;that
如图，一次函数的图象与x轴、y轴分别相交于点A、B，将△AOB沿直线AB翻折，得△ACB．若C(， )，则该一次函数的解析式为 ______ ．
在真空中波长是6×10-7 m的光是黄色光,波长是4×10-7 m的光是紫色光.现有一束频率v0=5×1014Hz的单色光,它在折射率n=1.5的玻璃中传播时的波长是多少?它在该
下列词语中，字形和加点的字的读音全都正确的一项是（） A、扛（káng）鼎之作 心宽体胖（pán） 模棱（léng）两可 舐（shì）犊情深 B、处
---Why does she always ask you for help? ---There is no one else ______, is there? A. who to tur
