YOU SAID:

I have the flu and will not be into work on Monday.

INTO JAPANESE

私はインフルエンザにかかっており、月曜日には効力を発揮しないでしょう。

BACK INTO ENGLISH

I have flu and will not take effect on Monday.

INTO JAPANESE

私はインフルエンザにかかっており、月曜日には効力を発揮しません。

BACK INTO ENGLISH

I have flu and will not take effect on Monday.