Sentence 1: At the expense of the middle class.

Sentence 2: It is at the expense of the middle class.
Is this second sentence entailed by the first?

Answer: yes

Sentence 1: Nowhere in the book does Hatfield warn the reader that he has altered details or created composite characters to protect his sources.

Sentence 2: Hatfield did in fact warn the readers in his book that he had altered some details.
Is this second sentence entailed by the first?

Answer: no

Sentence 1: However, further unrest led to more coups in 1971 and 1980, after which yet another, more restrictive, constitution was prepared.

Sentence 2: After the unrest caused more coups in 1971 and 1980, another, even more restrictive, constitution was prepared.
Is this second sentence entailed by the first?

Answer:
yes