QUES: Comparison of a back-translation with the original text is sometimes used as a check on the accuracy of the original translation, much as the accuracy of a mathematical operation is sometimes checked by reversing the operation. But the results of such reverse-translation operations, while useful as approximate checks, are not always precisely reliable. Back-translation must in general be less accurate than back-calculation because linguistic symbols (words) are often ambiguous, whereas mathematical symbols are intentionally unequivocal.

What operations are results from not always completely reliable?
What is the answer?
ANS: reverse-translation operations
QUES: Internal courtyards became more rare, except beside the stables, and the functional parts of the building were placed at the sides, or in separate buildings nearby hidden by trees. The views to and from the front and rear of the main block were concentrated on, with the side approaches usually much less important. The roof was typically invisible from the ground, though domes were sometimes visible in grander buildings. The roofline was generally clear of ornament except for a balustrade or the top of a pediment. Columns or pilasters, often topped by a pediment, were popular for ornament inside and out, and other ornament was generally geometrical or plant-based, rather than using the human figure.

What type of courtyard became more popular at this time
What is the answer?
ANS: unanswerable
QUES: During the night of December 2 and early morning of December 3, 1968, Kerry was in charge of a small boat operating near a peninsula north of Cam Ranh Bay together with a Swift boat (PCF-60). According to Kerry and the two crewmen who accompanied him that night, Patrick Runyon and William Zaladonis, they surprised a group of Vietnamese men unloading sampans at a river crossing, who began running and failed to obey an order to stop. As the men fled, Kerry and his crew opened fire on the sampans and destroyed them, then rapidly left. During this encounter, Kerry received a shrapnel wound in the left arm above the elbow. It was for this injury that Kerry received his first Purple Heart Medal.

Where was Kerry's boat on Dec 2-3, 1968?
What is the answer?
ANS:
near a peninsula north of Cam Ranh Bay