No one knows for certain what happened, but it's a fair bet that it was not an accident.
没有人知道究竟发生了什么,但几乎可以肯定这并非意外。
We should learn the value of money and learn how many hours' work has to be done before we can buy something.
我们应该认识到钱的价值,知道要干多少小时的活,我们才能买某件物品。