一种非同寻常、完全不像孩子该有的执着和极力控制的焦灼使他等待着。同时，他躺在水下散落着随他一同从上方落下的石子的白沙上，研究着隧洞的入口。
【正确答案】：A curious, most unchildlike persistence, a controlled impatience, made him wait. In the meantime, he lay underwater on the white sand, littered now by stones he had brought down from the upper air, and studied the entrance to the tunnel.
