1. Early next morning, she heard planes passing overhead and wondered how she could send a signal.
    第二天清晨，她听到头上有飞机飞过，却不知道怎样才能发出信号，

2. Everyone knows that if he shouts in the vicinity of a wall or a mountainside, an echo will come back.
    大家都知道，在墙壁或山腰附近发出的喊声，就会听到回声。

3. Early next morning, she heard planes passing overhead and wondered how she could send a signal.
    第二天一大早，她听到头顶上有飞机飞过，但不知道怎样才能发个信号。

4. Before returning home at night, he took a shower and changed back into his suit.
    晚上回家前,他洗个淋浴,又换上他那套西装.

5. But we do not need to send men down to get the oil out, as we must with other mineral deposits.
    但是，我们不必像开采其他矿藏那样，把人送到地下去把石油取出。

6. Because of this, we kept looking back, wondering if we were leaving a trail of oil and petrol behind us.
    因此，我们不时地掉过头，怀疑车后是否留下了机油和汽油的痕迹。

7. Before we had time to worry about what might happen, we were back on the plain again.
    我们还未来得及担心后果，车已重新开上了平地。

8. Before returning home at night, he took a shower and changed back into his suit.
    晚上回家前，他洗个淋浴，重新换上那身黑色西服。

9. By January 10th, I was back to where I had started from.
    到了1月10日，我恢复了原来的作息时间。

10. Back in the train, we told each other what a wonderful time we had had that day.
    回去的火车上，大家都说，这一天过得真愉快。