should

If you want to significantly improve your fluency in English, you should practice speaking every single day.

(Chinese) 如果你想显著提高英语流利度，你应该每天都练习口语。

The doctor strongly advised that he should rest at home for at least three days after the minor surgery.

(Chinese) 医生强烈建议他在微创手术后至少在家休息三天。