hardness and opportunity的用法和樣例：
例句
- America is the land of freedom and opportunity.
美國是一個擁有自由與機遇的國度。 - Based on the experience and models of Chinese teaching in Singapore, the paper discusses the challenges and opportunities of TCSL in a multi-lingual situation.
摘要本文以新加坡華語教學經驗與模式為基礎，探索在多語環境下漢語作為第二語言教學的挑戰與機遇。
