1、They could not provide adequate air cover for ground operations.
他們無法為地面作戰(zhàn)行動提供足夠的空中掩護。

2、The reasonable parameters of the convolute air cover and axial speed attenuation rule were found.
獲得了影響回旋氣幕形成各主要因素的合理參數(shù)以及軸向速度衰減規(guī)律。

3、The ships needed air cover once they reached enemy waters.
已到達敵方的水域，船只就需要空中掩護。