The supreme happiness of life is the conviction that we are loved.
生活中最大的幸福是坚信有人爱我们。
采矿业的成功来自于经济增长与环境责任的平衡。
You can't just give up on something because it's hard.
光波,无论是以太波还是其他波,在所有情况下都是时间上的周期性过程。