Security is always excessive until it's not enough.
Success is not final, failure is not fatal: it is the courage to continue that counts.
The future of coal lies in cleaner technologies and smarter resource management.
写作对我来说就像呼吸。我必须写作才能活下去。
表示论提供了表达许多数论现象的语言。
寂静中有音乐,如果你仔细聆听。