n.音变性,可移动性
He had been a rock in the shifting sands of her existence.
他一直是她曲折坎坷的生活中的主心骨。
He stopped, shifting his cane to his left hand.
他停了下来，将手杖移到左手。
It's impossible to prove him wrong because he keeps shifting his ground.
要证明他错是不可能的,因为他不断地改变立场.