已知：x2+mx+n=（x-5）（x+4），则m= ，n= ．
（x-5）（x+4）=x2-x-20，
∴m=-1，n=-20．
故答案为：-1，-20．
We should give the boy another chance _____ he has made some mistakes. [ ]
A. though
B. when
C. unless
D. because
ade some mistakes. [ ]