Bunuel
Any fairly experienced espionage agent knows that a good vodka martini should not be stirred, but instead shook.
A. knows that a good vodka martini should not be stirred, but instead shook
B. knows that a good vodka martini should be shook, not stirred
C. knows that a good vodka martini should not be stirs, but shaken
D. knows that a good vodka martini should not be stirred, but shaken
E. know that good vodka martinis should be shaken, not stirred
OFFICIAL EXPLANATION
Any fairly experienced espionage agent knows that a good vodka martini should not be stirred, but instead shook.A. knows that a good vodka martini should not be stirred, but instead shook
This answer choice is grammatically incorrect. Only the first verb of a sentence should be conjugated. Shook is not the first verb and should thus be unconjugated. However, shook is conjugated - it is the past form (V2) of shake.
Also note that should not be stirred but shook is a passive construction which should be: Be + V3. However, here shook is not in V3 form. The verb stirred is fine because the V2 and V3 forms of this verb are the same (stirred). B. knows that a good vodka martini should be shook, not stirred
This answer choice repeats the original mistake. Only the first verb of a sentence should be conjugated. Shook is not the first verb and should thus be unconjugated. However, shook is conjugated - it is the past form (V2) of shake.
Also note that should be shook, not stirred is a passive construction which should be: Be + V3. However, here shook is not in V3 form. The verb stirred is fine because the V2 and V3 forms of this verb are the same (stirred).C. knows that a good vodka martini should not be stirs, but shaken
This answer choice is grammatically incorrect. Only the first verb of a sentence should be conjugated. Stirs is not the first verb and should thus be unconjugated. However, stirs is conjugated - it is the present form (V1) of stir.
Also note that should not be stirs but shaken is a passive construction which should be: Be + V3. However, here stirs is not in V3 form. This answer choice does use the verb shaken correctly as this is the V3 form of the verb shake.D. knows that a good vodka martini should not be stirred, but shaken
Admittedly, this answer choice is not the most concise of the five answer choices. However, it is the only grammatically correct one as it uses the V3 verb forms shaken and stirred correctly. Remember that on the GMAT, grammar overrides style. The correct answer can be stylistically flawed (i.e., redundant or ambiguous), but it can never be grammatically incorrect.E. know that good vodka martinis should be shaken, not stirred
While this answer choice corrects the original Verb Forms and Passive mistake by using the V3 verb forms shaken and stirred, it creates a new one. The singular subject agent does not agree with the plural verb know.