考虑到干扰控制，城区三扇区站水平波束宽度一般不大于（）
A.45°
B.90°
C.120°
D.65°
参考答案：D
下列多项式中，能在实数范围内分解因式的是（ ）
A．2x2-x+1
B．-2x2+x+1
C．2x2+2x+1
D．-2x2+x-1
Dan devoted all the energy he had_____________ his novel.[ ]
A. to writing
B. to write
C. write
D. written
