YOU SAID:
There was a party this weekend
INTO JAPANESE
当事者はこの週末がありました
BACK INTO ENGLISH
The party, there was this weekend
INTO JAPANESE
当事者は、この週末がありました
BACK INTO ENGLISH
The parties, there was this weekend
INTO JAPANESE
当事者は、この週末がありました
BACK INTO ENGLISH
The parties, there was this weekend
That didn't even make that much sense in English.