Fill in the blank with suitable word. Barking dogs ____ bite.

Concept: An idiom is a fixed expression whose overall meaning is understood as a whole and cannot be derived from the literal meaning of its individual words; in a sentence-completion item, the blank must be filled with the exact word that completes the standard, fixed form of the idiom.

Application: The sentence completes the well-known English idiom “Barking dogs seldom bite”, which means that people who make a lot of noise, threats, or empty warnings rarely follow through with real action. The word that correctly completes this fixed idiom is “seldom”.

Contrast:

• “regularly” describes a habitual, repeated action; using it would mean the noisy ones act on their threats as a routine, which contradicts the idiom’s meaning that they rarely act.

• “only” introduces an exclusive condition and does not match the fixed wording of the idiom.

• “frequently” asserts a high rate of occurrence, the opposite of what the idiom conveys.

Result: So the correct completion is “seldom”, giving the idiom “Barking dogs seldom bite.”