等腰三角形的底和腰是方程x2-6x+8=0的两个根,则这个三角形的周长是( )
A:8
B:10
C:8或10
D:不能确定
按要求完成小题:
—He often ____(watch) TV.
儿童易患佝偻病,是因为儿童正处于生长发育期更需要( )
— How old is Mr. Gao?
— He is more than thirty. I think he was born _________.