蚕蛾和蝴蝶的生长发育都要经过____。
—Why didn't you cry for help when you were robbed (被抢劫)?
—If I opened my mouth, they might find my four gold teeth. That would be !
下列关于岳飞的说法，正确的是：（ ）
设平面α的法向量为（1，2，﹣2），平面β的法向量为（﹣2，﹣4，k），若α∥β，则k=____
