YOU SAID:

the dog was really sad today cause his favourite toy exploded in the microwave

INTO JAPANESE

犬は今日本当に悲しかったので彼のお気に入りのおもちゃが電子レンジで爆発した

BACK INTO ENGLISH

The dog was so sad today that his favorite toy exploded in the microwave

INTO JAPANESE

犬は今日とても悲しかったので、彼のお気に入りのおもちゃは電子レンジで爆発しました

BACK INTO ENGLISH

The dog was so sad today that his favorite toy exploded in the microwave