An oil spill _______ (BE) incredibly dangerous for wildlife
An oil spill MUST BE incredibly dangerous for wildlife
We don't know what caused the accident , it _______ (have/be) a gas leak
We don't know what caused the accident , it MIGHT HAVE BEEN a gas leak
Come and take a look at the fireworks , you ________ enjoyt it
Come and take a look at the fireworks , you MIGHT enjoy it