Determine whether the underlying phrase or clause in each sentence is restrictive or nonrestrictive.
Lighting that strikes in dry forests can cause forest fires.
To determine whether the underlying phrase or clause in the sentence is restrictive or nonrestrictive, we need to analyze its function and impact on the sentence's meaning.
In the given sentence, the phrase "that strikes in dry forests" provides additional information about the noun "lighting." To determine its restrictiveness, we need to ask whether it is essential for understanding the sentence's meaning or if it can be removed without significantly changing the sentence's overall message.
If we remove the phrase, the sentence becomes "Lighting can cause forest fires." While this sentence is still grammatically correct, it lacks the specific context of where the lightning strikes occur. Therefore, the phrase "that strikes in dry forests" is necessary for understanding the sentence's complete meaning and is considered a restrictive phrase.
In conclusion, the underlying phrase in the sentence "Lighting that strikes in dry forests can cause forest fires" is restrictive.