Sentence 1: Its harbour, from which Milesian ships set forth to found over 100 colonies during the seventh and eighth centuries b.c. , is now a frog-filled marsh.

Sentence 2: The Milesian ships never created colonies as their mission was to only trade.
Is this second sentence entailed by the first?

Answer: no

Sentence 1: Although the site is still under excavation, you can visit it.

Sentence 2: You can visit this site, even though they are still excavating it.
Is this second sentence entailed by the first?

Answer: yes

Sentence 1: uh well they say that from that space needle up in Toronto you can see the lights of Rochester on a clear night

Sentence 2: You can see Rochester from Toronto sometimes but it's usually too cloudy.
Is this second sentence entailed by the first?

Answer:
it is not possible to tell