It means the time used in the past is already redundant, and that you can learn from the past to improve next time.
Answer:
this is true if anything has sources it is credible
B. Would be the answer. This is because if you abbreviate a word, there has to be a period. States aren't abbreviated though.
The answer is D because you need the word and at the very last name and you need commas in all the blanks.