Story needs to be completed:
Matt was running late for a vet appointment so he got on a train and luckily the 
OPTIONS:
- appointment was fast.
- train was fast.

My choice:
train was fast.
Problem: Continue the following story.

At the mall on Friday, Laura paid Jennifer for the diamonds because 
OPTIONS:
- Laura was the vendor.
- Jennifer was the vendor.
Here's how I want to continue it: Jennifer was the vendor.
Problem: Aaron's recreational vehicle was really just a trailer compared to Kevin's behemoth. 
OPTIONS:
- Aaron had a grander model.
- Kevin had a grander model.

My choice: Kevin had a grander model.
[Q]: How does the sentence end?

So 
OPTIONS:
- Christopher kicks the kitten because Christopher likes pets and Jason hates them with a deep passion.
- Jason kicks the kitten because Christopher likes pets and Jason hates them with a deep passion.

[A]: Jason kicks the kitten because Christopher likes pets and Jason hates them with a deep passion.
QUES: Continue writing.

The tickets for the band concert sold out very quickly. The 

OPTIONS:
- tickets were very popular because they were cheap.
- band were very popular because they were cheap.
+++++++++
ANS: tickets were very popular because they were cheap.
QUES: Continue writing.

Matthew tried to be stealthy while planning a party for Donald, but 

OPTIONS:
- Matthew found out from someone who couldn't keep a secret.
- Donald found out from someone who couldn't keep a secret.
+++++++++
ANS:
Donald found out from someone who couldn't keep a secret.