下列哪一条经纬线与本初子午线一样长[ ]
A、23.5°S
B、66.5°N
C、20°W
D、赤道
答案：C
I’d like to see you off at the airport. Could you tell me _____ ?
A．when your plane took off
B．when did your plane take off
C．when your plane takes off
D．when does your plane take off
（）管线钢种属于正在开发的。
A、X70
B、X65
C、X130
D、X80
