Problem: If "By rolling over in her upper berth, Tatyana could look over the edge of it and see her mother plainly. How very small and straight and rigid she lay in the bunk below! Her eyes were closed, but Tatyana doubted if she slept.", does it follow that "Tatyana doubted if Tatyana slept."?

Answer: no

Problem: If "John ordered Bill to leave, so an hour later he left.", does it follow that "Bill left."?

Answer: yes

Problem: If "We went to the lake, because a shark had been seen at the ocean beach, so it was a dangerous place to swim.", does it follow that "The ocean beach was a dangerous place to swim."?

Answer: yes

Problem: If "Although they ran at about the same speed, Sue beat Sally because she had such a good start.", does it follow that "Sue had such a good start."?

Answer:
yes