在地面传真图上冷锋的符号为（）。
A．蓝色线条
B．带有几个锯齿形符号的线条
C．加粗线
D．带有几个半圆形符号的线条
参考答案：B
The conference ________ a full week by the time it ends. [ ]
A. must have lasted
B. would have lasted
C. will have lasted
D. has lasted
《机动车运行安全技术条件》（GB7258-2004）明确规定，三轮汽车、低速货车的比功率不应小于（）KW/T。
A、4.5
B、5.0
C、6.0
D、4.0
