The correct spelling of critical+ly is <em>critically</em>.
<em>Critically</em> is an adverb formed by the root adjective <em>critical</em> and the suffix -ly.
In general, to form adverbs from an adjective we add the suffix -ly after the adjectives' last syllable.
Adjectives that end with one L keep it when adding the suffix -ly.
This is the case of the adverb <em>critically</em>.
Other examples are:
- Typical⇒ typically
- radical ⇒radically
- practical ⇒practically
- cool ⇒ coolly
If the adjective ends with double L, we drop one before adding the suffix:
You can learn more about suffix -ly in the link below:
brainly.com/question/13903218
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