[Q]: How does the sentence end?

Mark told Jason never to put his plants in copper containers, but to use clay pots instead because the 

[A]: copper was toxic.


[Q]: How does the sentence end?

Dennis was less impressed with the crystals than Jason, because 

[A]: Dennis was seeing the crystals for the tenth time.


[Q]: How does the sentence end?

Amy had to change their car coolant but not Christine because the car of 

[A]:
Christine was cool.