1. Let me sound one note of warning.
    在此我警告一句。

2. In this part of the cave, they could hear an insistent booming sound .
    在洞穴的这块地方，他们能够听到持续的轰响.

3. I heard sound of footsteps on the floor.
    我听到地板上的脚步声。

4. I was roused by the sound of a bell.
    钟声把我吵醒了.

5. In this part of the cave, they could hear an insistent booming sound
    在这儿，他们可以听见一种连续不断的轰鸣声。

6. Is overflowing with the sound.
    都被这歌声淹没。

7. In three years of day and night effort, Bell figured out how to send sound over a changing electric current.
    经过三年夜以继日的努力，贝尔弄清了如何通过波动的电流传送声音。

8. When these made a sound, they had to make a note of what they were doing and assess how happy and alert they felt.
    当发出声响时，他们就要记下当时孩子们正在干什么，并评估孩子们从中所感受到的快乐和反应的敏捷程度。