设置在线路终端处的电杆称为（）
A.直线杆
B.耐张杆
C.转角杆
D.终端杆
参考答案：D
Mum ______ to us. “Be quiet! Your little sister is sleeping.”
A．shouted
B．explained
C．whispered
D．replied
The world is changing fast.I strongly believe that one will easily fall behind____he keeps on leaming. [ ]
A. unless
B. if
C. when
D. as
