梯度风
参考答案：
自由大气中作曲线运动的空气，当G、A、C这个力达到平衡时形成的风称为梯度风
— How was your recent trip to Sichuan?
— I've never had ________ one before. [ ]
A. a pleasant
B. a more pleasant
C. a most pleasant
D. the most pleasant
PDCA模式是计划→实施→检查→（）。
A、奖评
B、总结
C、改进
D、评比
never had ________ one before. [ ]