Premise:
"And what's the proper etiquette for an e-mail kiss-off?"
Hypothesis: Whats the etiquette for email kiss off

yes

Premise:
"At the foot of the castle was Nor' Loch, a large expanse of water that required draining."
Hypothesis: Nor' Loch took 3 years to drain.

it is not possible to tell

Premise:
"The Spanish settled the land and grew crops here in the 17th century, but the fine great house was built by English colonists in the 18th century."
Hypothesis: The Spanish settled the land before the English built the house.
yes