Problem: Wwo sentences:
Only 29 families of frogs are known and most were identified and described in the mid-1800s and the last in 1926 .
Only 29 families of frogs are known , most of which were named by the mid-1800s .
Do they have the same meaning?

Answer: no

Problem: Wwo sentences:
A COUPLE have been arrested for starving their four sons while letting their daughters feast in front of them .
A couple starved their four adopted sons for years while allowing their daughters to feast on takeaways , police and neighbours said today .
Do they have the same meaning?

Answer: yes

Problem: Wwo sentences:
Massachusetts does not have a state death penalty , and only once before - in Michigan - has the federal death penalty been given in a state without capital punishment .
Massachusetts has no state death penalty , and only once before -- in Michigan -- has the federal death penalty been given in a state without capital punishment .
Do they have the same meaning?

Answer: yes

Problem: Wwo sentences:
Immediately after the blast , people portraying some of the 150 " victims " stumbled amid the wreckage as emergency vehicles converged on the scene .
Immediately after the small explosion , people portraying victims stumbled amid the wreckage as fire trucks and other emergency vehicles converged .
Do they have the same meaning?

Answer:
yes