YOU SAID:

Yesterday wasn't so bad.

INTO JAPANESE

昨日は、そう悪くはなかった。

BACK INTO ENGLISH

Yesterday, it wasn't bad.

INTO JAPANESE

昨日、それは悪くはなかった。

BACK INTO ENGLISH

Was not yesterday, it is bad.

INTO JAPANESE

でした、昨日は悪いです。

BACK INTO ENGLISH

In yesterday, that is bad.

INTO JAPANESE

昨日、それは悪いです。

BACK INTO ENGLISH

Yesterday, it is bad.

INTO JAPANESE

昨日、それは悪いです。

BACK INTO ENGLISH

Yesterday, it is bad.