量子密码学不依赖于数学问题的难度，而是依赖于物理学的基本定律。

Mrs. March knew that experience was an excellent teacher, and when it was possible she left her children to learn alone the lessons which she would gladly have made easier, if they had not objected to taking advice as much as they did salts and senna.

谗言不会自己来，而是因为心中有猜疑才来；离间的话不会自己钻入，而是因为有了缝隙才来。