Definition
Used to indicate that an action is advisable or necessary.
最好、应該
You had best start preparing now, or you will not have enough time.
你最好現在開始準備，否則時間會不夠。
We had best reach the campsite before dark.
我們最好在天黑前到達營地。
They had best submit the report as soon as possible, or they will face penalties.
他們最好盡快提交報告，否則將面臨處罰。