MATH PUZZLE: Can you replace...

A police officer came upon a terrible wreck where the driver and passenger had been killed. As he looked upon the wreckage a little monkey came out of the brush and hopped around the crashed car.
The officer looked down at the monkey and said, "I wish you could talk."
The monkey looked up at the officer and shook his head up and down.
"You can understand what I'm saying?" asked the officer.
Again, the monkey shook his head up and down.
"Well, did you see this?"
"Yes," motioned the monkey.
"What happened?"
The monkey pretended to have a can in his hand and turned it up by his mouth.
"They were drinking?" asked the officer.
The monkey shakes his head "Yes."
"What else?" The monkey pinched his fingers together and held them to his mouth.
"They were smoking marijuana?"
The monkey shakes his head "Yes."
"What else?" The monkey motioned "kissing."
"They were kissing, too?" asked the astounded officer.
The monkey shakes his head "Yes."
"Now wait, you're saying your owners were drinking, smoking and kissing before they wrecked."
The monkey shakes his head "Yes."
"What were you doing during all this?"
"Driving," motioned the monkey.