唯一存在的限制是你给自己设置的。
The only limits that exist are the ones you place on yourself.
The only way to know your limits is to go beyond them.
A happy person is not a person in a certain set of circumstances, but rather a person with a certain set of attitudes.
大国政治的悲剧在于,即使是善意的国家也被迫采取可能导致冲突和战争的行为。