[semantics] Nuances of near-synonymous PPs

[qinhh76]

I'm doing research on pairs of near-synonymous prepositional phrases but very puzzled by the nuances of the following pairs, which are all from BNC (British National Corpus). Looking forward to your insights.

(1) a. We stood up and left the house by the back door.
b. He entered the house through the back door.

(2) a. All such grafts will die form lack of water.
b. Farmers are losing crops for lack of water.

(3) a. By conservative estimates, 2.5 million people around the world die each year from smoking cigarettes.
b. The same thing that's happened in Ireland has happened all over the world.

[Soup]

(1) a. We stood up and left the house by [means of/using] the back door.
(1) b. He entered the house through the back door.

(2) a. All such grafts will die from lack of water.
(2) b. Farmers are losing crops for/because of lack of water.

(3) a. By conservative estimates, 2.5 million people [from] around the world die each year from smoking cigarettes.
b. The same thing that's happened in Ireland has happened all over the world.

[qinhh76]

Thanks for your thoughts. In language alternation in form brings about change in meaning. Can you explain them in detail? I wonder if "through" also expresses the notion of "means" in the above sentence, and can the three pairs be interchangeable without changing the meanings?

[Soup]

Thanks for your thoughts. In language alternation in form brings about change in meaning.

But you're not dealing with form--you're dealing with ellipsis.

I wonder if "through" also expresses the notion of "means" in the above sentence,

As in by way of [using], yes.