如图，△ABC和△ABD都是⊙O的内接三角形，圆心O在边AB上，边AD分别与BC，OC交于E，F两点，点C为的中点． （1）求证：OF∥BD； （2）若，且⊙O的半径R=6cm
俗话说“龙生龙，凤生凤，老鼠生儿会打洞”，这说明了生物的( )A．进化现象B．适应现象C．遗传现象D．变异现象
一个质点由静止开始沿直线运动，速度随位移变化的图线如图7所示，关于质点的运动，下列说法正确的是( ) A．质点做匀速直线运动 B．质点做匀加速
.新中国成立之初，独立自主和平外交方针的主要内容有（ ） ①“另起炉灶”②“打扫干净屋子再请客”③“一边倒”④求同存异 A.①②③④
He talked again and again to his friend about careful driving, but_________just turned a deaf ear to his words. A．another B．other C．others D．the other
The League secretary and monitor ___ asked to make a speech at the meeting. A. is B. was C. are D. were
现有无标签的稀蛋清、葡萄糖、淀粉和淀粉酶溶液各一瓶，可用双缩脲试剂、斐林试剂和淀粉溶液将它们鉴定出来。请回答： (1)用一种试剂将上述4种溶
What makes a gift special? Is it the price you see on the gift receipt? Or is it the look on the recipient’s face when they receive it that determines the true value? What gift is worth the most?
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