You only need one word from each pair.
basic, fundamental reason, purpose
each, every issues, concerns
full, complete final, conclusive
simple, elementary concept, idea
1. He woke up at 6 A.M.1 this morning2. 1. He woke up at 6 A.M.
2. The basic1 fundamental2 essentials3 2. The fundamentals of an operating of an operating system are simply1 and system are simply these.