句子使用not necessarily表达否定限制，突出感恩形式的多样性。
A person's situation, whether bitter or sweet, often depends on their subjective mindset.
Be detached in self-conduct, amiable in dealing with others, clear-minded in leisure, decisive in matters, calm in success, and composed in adversity.
The magnificence of a waterfall is often formed when there is no way back.
Gratitude does not necessarily mean repaying great favors or heavy gifts; it can be a casual reminder or encouragement from others, or a warm phone call of greeting and blessing.
There are two types of people in this world who are most formidable: those who refuse to learn, and those who are reckless with their lives.
一个人的处境是苦是乐，往往取决于主观心态。
自处超然，处人蔼然，无事澄然，处事断然，得意淡然，失意泰然。
瀑布的壮观，往往是在没有退路时形成的。
感恩并不一定意味着回报大恩大德或重金馈赠，它可能只是别人不经意间的提醒或鼓励，亦或是热情的电话问候与祝福。
世上有两种人最可怕：一种是不愿学习的，一种是不要命的。