YOU SAID:
この夏休みは働こうと思いました。
INTO JAPANESE
この夏休みは働こうと思いました。
BACK INTO ENGLISH
I thought I would work this summer vacation.
INTO JAPANESE
私はこの夏休みに働こうと思った。
BACK INTO ENGLISH
I thought I would work this summer vacation.
That didn't even make that much sense in English.