若x2+kx+4是一个完全平方式，则常数k的值为______．
∵x2+kx+4=x2+kx+22，
∴kx=±2×2x，
解得k=±4．
故答案为：±4．
向权利人发权属证书是权属登记程序的最后一项。 （ ）
After suffering a heart attack, Michael Jackson was pronounced dead, ____ a tragic end to the world' s
most popular entertainer.
A. to mark
B. marking
C. marked
D. having marked
