河冰结合，非一日之寒；积土成山，非斯须之作。
解释：河水成冰，不是一日的寒冷所致；积土成为高山，不是须臾的工夫就能完成。
The first duty of the sovereign， that of protecting the society from the violence and invasion of other independent societies， can be performed only by means of a military force.
The concept of a black hole firewall challenges our understanding of quantum mechanics and general relativity.
Every life is an archive.
