"although the sun was shining, it wasn't that warm" is the correct answer because it contains a main clause (it wasn't that warm) and a prepositional phrase (although the sun was shining,). Hope this helps :)
Answer:
The first one.
Explanation:
I think that the first one is right because it seems that the massage so important because he (Arthur ) sent the massage using the U-boat.
Answer:
Alex had helped poor people
Alex is helping poor people
