YOU SAID:
I am going to the market.
INTO JAPANESE
私はマーケットに行っている。
BACK INTO ENGLISH
I'm going to the market.
INTO JAPANESE
私は市場に行きます。
BACK INTO ENGLISH
I will go to the market.
INTO JAPANESE
市場に行く。
BACK INTO ENGLISH
I will go to the market.
That didn't even make that much sense in English.