The sentence is given: They could easily win the game.
I must transform it using the word "chance". Which one is right:
They had every chance of winning the game.
or
They have every chance of winning the game.
To me, it's obvious that the right variant is 1. But The keys say it's 2.
The choices in your transformation are identical except for the tense: have versus had.
You need to choose the answer with the correct tense. The given sentence refers to a future possibility.
Compare:
They could win the game tomorrow.
They could have won the game yesterday, if they hadn't committed so many fouls.
When we refer to a future possibility, we use could + {bare infinitive}. When we refer to a past possibility, we use could plus the perfect: have + {past participle}.
In the transformations with "every chance", had and had are not helper (auxiliary) verbs but the lexical verb "to have", meaning "to possess"; whereas in the the phrase "have won the game", have is a helper verb forming the perfect.
