A black hole is a region of space where the gravitational pull is too strong that nothing can escape.
A. 1. some region of space 2. a region out of space
3. the region with spacing 4. any region for spacing
B. 1. by which the gravitational pull
2. while pulling the gravitation
3. when pulled by the gravitation
4. with which the gravitational pull
C. 1. strong so that
2. such strong power that
3. strong enough that
4. so strong that
D. 1. anything can escape
2. everything can be escaping
3. something can escape
4. nothing can be escaping