发射同步卫星与地球自转速度密切相关,据此分析下列发射场中最有利于卫星发射的[ ]
A、拜科努尔(46°N)
B、肯尼迪(28°N)
C、酒泉(40°N)
D、库鲁(5°N)
答案:D
— Have you given Mr. Li the message?
— Not yet. I will give it to him as soon as he ______. [ ]
A. is coming back
B. came back
C. comes back
D. will come back
坐骨神经痛最常见的病因是()。
A.马尾肿物
B.腰椎间盘突出
C.坐骨神经外伤
D.腰骶椎炎
E.腰骶神经根炎