[Q]: How does the sentence end?

I tried to write a letter but switched from the blue pen to the black pen since the

[A]: black pen's ink well was full.

[Q]: How does the sentence end?

Christopher was ahead of Steven in the line to use the rope swing, because

[A]: Christopher got there first.

[Q]: How does the sentence end?

Sarah had worse symptoms than Tanya, so

[A]:
Tanya was seen by the emergency room doctor second.