busy

周一是我一周中最忙碌的日子。

Monday is my ___busiest day of the week.

自从升职后，他比以前更忙了。

He's much ___busier now after getting promoted.

这条街道在高峰时段非常繁忙。

This street is very ___busy during rush hour.

十二月通常是一年中最忙碌的月份。

December is usually the ___busiest month of the year.