一列平面简谐波沿x轴正方向以波速 u 传播,已知坐标原点处质点作谐振动的振幅为a、角频率为、位移~时间曲线如图所示。则坐标原点处的振动方程以及平面简谐波的波函数分别为
选出声母为n的音节( )
assess, evidence, margin, prosperous, maximum ⑤ the great promise of trade is its potential to promote mutual ______ and to strengthen the bonds between sovereign nations.