He (not go) to work yesterday because he (be) sick.
He DIDN'T GO to work yesterday because he WAS sick.
They (play) football last weekend. It (be) raining so they (get) sick.
They PLAYED football last weekend. It WAS raining so they GOT sick.
He (not feel) good yesterday. He (be) sick.
He DID NOT FEEL good yesterday. He WAS sick.