将下列图片和句子配对。
① ____ A. dog
② ____ B. bird
③ ____ C. pig
④ ____ D. monkey
⑤ ____ E. cow
Some students spend ________ time on the Internet. They forget to study, eat and sleep. They can't even communicate with people in real life.
如图,在平面直角坐标系中,点A的坐标为(0,2),点P(t,0)在x轴上,B是线段PA的中点.将线段PB绕着点P顺时针方向旋转900,得到线段PC,连结OB、BC. (1)判断△PBC的形状,并简要说明理由; (2)当t>0时,试问:以P、O、B、C为顶点的四边形能否为平行四边形?若能,求出相应的t 的值?若不能,请说明理由; (3)当t为何值时,△AOP与△APC相似?