Usage patterns
〈物〉の状態は良だthe condition of X is (rated) good
The condition of this used car is rated Good.
〈事〉の成績は良だったthe grade for X was a Good (B)
My grade in math was a Good.
〈事〉の評価は良the rating for X is 'Good'
The evaluation of the test results was 'Good'.
Expressions
狡兎良狗when the enemy is defeated, the victorious soldiers can be killed off