modal verb + have + past participle

Looking out of your window in the morning, you notice that all the flowers in your garden are missing.
What happened? You take a guess at it:

"A rabbit might have eaten all my flowers."

Let's take a look at that form.

might (modal) + have + eaten (past participle verb)

We use the modal might (you can also use may or could) because they show that we are not 100% sure about what happened. We are speculating about past events (guessing what we think happened). We then must use have followed by a past participle verb. We use 'must' when we have a stronger opinion about what happened.

Here are some other examples:

"My neighbour could have stolen the flowers"

"The wind might have blown them all away."

You can find more information here: Speculating about past events

• Erica must ___ gone out. I can't see her.
  
  could
  have
  has
  
  
• He looks tired. He might have ___ awake all night.
  
  been
  has
  an
  could
  
  
• I think James must have ___ all the milk. There's none left.
  
  drink
  drank
  drinking
  drunk
  
  
• Look at Lilly's suntan. She must have ___ somewhere hot on vactaion.
  
  going
  goes
  go
  gone
  
  
• She's late. She may have ___ the wrong road.
  
  took
  taken
  taked
  has