If we're all prepared to recycle paper, thousands of trees could be saved every day.
如果纸能被循环利用,那么每天千千万万的树木就可得以挽救。
The second marks the arrival of transverse vibrations which travel more slowly and arrive several minutes after the first.
然后记录下的是横向波的到达,横向波比纵向波传播得慢,在纵向波到达几分钟后才能到达。