Identify the error, if any, in the sentence below.
Determination ofA the long-term effects ofB aerosols on the upper atmosphere isC currently one of the more challengingD problems in climate research. No errorE.
This seems ok, but there’s actually a problem. “More challenging” would only be appropriate if you were comparing two items. Here, you would need to say “most challenging.” English speakers often confuse usage of the comparative and the superlative. The comparative is used when there are two things involved; the superlative is used when there are three or more things involved. For example, you would say, “Of the twins, John is the smarter,” and “Of the triplets, John is the smartest.” The answer is (D).
source: majortests.com
