The fat man was very heavy and soon the chair was in ____ (piece).
函数y=tan35x是 ()
Our teachers were very happy because ______ failed the exam.
已知4x2m﹣n﹣4﹣5yn﹣1=8是关于x,y的二元一次方程,则m=____,n=____
孔雀开屏、青蛙的高昂鸣叫都是防御行为。