EGC业务包括()。
A、海上安全网业务和船队业务
B、航行警告业务和船队业务
C、航行警告业务和气象警告业务
D、航行警告业务和NAVTEX业务
参考答案:A
The book The Natural Approach: Language Acquisition in the Classroom was produced by ______ in 1983.
A. Krashen and Halliday B. Hymes and WilkinsC. Krashen and Terrell D. Halliday and Hymes
Y1ll型封隔器的剪断销钉的直径为3.6mm时,它的剪断力为多少?(设销钉材料的剪切强度极限应力Υb=392MPa,销钉按一个计算)。