On the SAT Writing section, there are five conjunctions that must always be preceded by a semicolon when they are used to begin a clause.
The first two appear very frequently while the other three are less common, but the rule is the same for all of them. The inclusion of these conjunctions is usually a dead giveaway that a question is testing semicolon usage, so if you see one of them, first check whether there is an answer that includes a semicolon; it will virtually always be correct. For example:
Researchers believe that genes could affect the amount of caffeine people consume, environmental factors are known to play an important role as well.
(A) consume, environmental factors are known to play an important role
(B) consume; but environmental factors are known to play an important role
(C) consume, an important role is known to be played by environmental factors
(D) consume; however, environmental factors are known to play an important role
(E) consume, with environmental factors being known to play an important role
If you can recognize the original version of the sentence as a comma splice (two sentences separated by a comma), you’re already ahead of the game. What you may not realize, however, is that you don’t actually have to reach each answer through word by word, trying to find the best way to fix the sentence.
Since semicolons are one of the most common ways to fix comma splices, any answer that contains one has a pretty good chance of being right. Furthermore, any answer that contains “semicolon + however,” is usually going to be correct. So if you scan through the answers and spot that choice D contains just that, you already know that you’ve probably found that right answer without even having to read through the other options.
To be on the safe side, you do need to plug the answer back into the sentence and check that it makes sense (it does), but working like this can save you an awful lot of time and worry.