Rickooreo wrote:
I thought that since the intended meaning of the question is to make comparison between two period, it should be one sentence and not two different sentence, just as
A is smarter than B
A is smart. B is not as smart as A.
This judgment, like all other judgments about the message / intended meaning of a sentence, needs to be informed by the actual content of the sentence.
In this case, it's plain at a glance that the sentence provides
two specific statistics, one for each timeframe cited. This means that the sentence CAN'T be phrased in terms of a comparative (
-er form, like "smarter" in your example).
Instead, there are two types of ways in which these kinds of sentences (with two quantitative specifics, between which the intended comparison is implied and left to the reader to infer) are most often written:
• As two altogether separate clauses—linked by a semicolon, so as to link them into what's still technically a single larger sentence (since SC conventions prohibit having more than one sentence in a single problem);
OR
• With "
[statistic], (as) compared to/with
[other statistic]".
The latter construction does, by the way, require that "compared to/with" be followed
directly by the second statistic. So, e.g., the construction of choice D is incorrect here; we'd need "compared with nearly 6 hours..." (not "compared with
a figure of nearly 6 hours...").