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。
In spite of all that has been said, the tourists have been picking leaves and cutting their names on the tree-trunk.
尽管有上述种种说法,但游客们还是照常摘树叶和把他们的名字刻在树干上。