对于IPTV组播业务，FTTH的应用类型宜将（）设置为组播复制点，FTTB的应用类型宜将（）设置为组播复制点。
参考答案：OLT；MDU（ONU）
______by the advances in technology, many farmers have set up wind farms on their land. [ ]
A. Being encouraged
B. Encouraging
C. Encouraged
D. Having encouraged
简述飞机的尾翼主要功能？
