This question tests your understanding of English idioms and verb patterns. The correct phrase is "It is no use crying over spilt milk," which means it's pointless to regret something that has already happened and cannot be changed.

Step 1: Analyze the first blank
The structure "It is no use" is followed by a gerund (verb + -ing). Therefore, "crying" is the correct form, not "to cry" (infinitive) or "cry" (base form).

Step 2: Analyze the second blank
The idiom uses the adjective "spilt" (or "spilled") to describe the milk. "Spilt" here functions as a past participle adjective modifying "milk," meaning the milk has already been spilled. "Spilling" would be incorrect because it suggests the action is currently happening, which doesn't fit the completed action described by the idiom.

Final Answer: The most appropriate words to fill in the blanks are crying and spilt.

Related Topics & Theory

Gerunds after expressions: Certain phrases like "It is no use," "It is worth," and "There is no point" are followed by a gerund.

Participial Adjectives: Past participles (e.g., broken, spilt, written) can be used as adjectives to describe a noun's state.

Idioms: This is a fixed expression. The words cannot be arbitrarily changed.

Key Formulae/Rules

Rule 1: It is no use + gerund (verb-ing)

Rule 2: The idiom is fixed: "crying over spilt milk"