Answer:
if the context clues are inadequate.
if the surrounding words are unfamiliar.
Explanation:
Using context in order to determine the meaning of a word is an extremely effective strategy, and one that should be used in almost all occasions. However, there are some cases in which this might not be the best strategy to follow. If the context clues that you find are inadequate, they might not help you determine the right meaning of a word. Moreover, if the surrounding words are unfamiliar, this strategy might not work either.
