Short-wave radio uses the 20-50 metre band.

　　短波收音機(jī)用的波段是20–50米。

　　He greeted them with a wave and a broad smile.

　　他咧嘴笑著揮手和他們打招呼。

　　The nation had been buffeted by a wave of strikes.

　　罷工浪潮使這個(gè)國家受到了重創(chuàng)。

　　She was apt to raise her voice and wave her hands about.

　　她常常提高嗓門并揮舞雙手。

　　A wave of superstitious fear spread among the townspeople.

　　一股迷信的恐懼浪潮在城里人中蔓延。