QUES: Q: What symbol set has a defining property of ambiguity?
A: Back-translation must in general be less accurate than back-calculation because linguistic symbols (words) are often ambiguous, whereas mathematical symbols are intentionally unequivocal.
Does the answer answer the question?

ANS: yes

QUES: Q: For what reason did Moody's Investor Services downgrade nine Portuguese banks in 2011?
A: In October 2011, Moody's Investor Services downgraded nine Portuguese banks due to financial weakness.
Does the answer answer the question?

ANS: yes

QUES: Q: Modern Greek theater began when?
A: The modern Greek theatre was born after the Greek independence, in the early 19th century, and initially was influenced by the Heptanesean theatre and melodrama, such as the Italian opera.
Does the answer answer the question?

ANS: yes

QUES: Q: Why was green chosen for a number of new European political parties in the 1980s?
A: In the 1980s green became the color of a number of new European political parties organized around an agenda of environmentalism.
Does the answer answer the question?

ANS:
yes