Quack is the sound made by ducks, which belong to the鸭科 Phasianidae and the鸭亚科 Anatidae in the family Anatidae, also known as real ducks. Ducks have a smaller body size than most other duck species, with short necks and larger beaks that grow larger as the species progresses. Legs are located behind the body, resembling those of swans, making their walk sluggish. Most true ducks, including those inaccurately referred to as "雁" by some, possess the following distinctive features: both males and females undergo annual moltings twice, and each brood incubates several eggs, which possess smooth shells. Hens cover their legs with overlapping scales, displaying varying degrees of sex differentiation in their vocalizations. The word "quack" primarily refers to the characteristic sound made by ducks, specifically in English. It is used metaphorically or colloquially to describe any sound, regardless of its source or classification, that sounds like the call of a duck. In this context, it denotes the collective name for all鸭科鸭亚科水禽 within the鸭属 Phasianidae and the鸭亚科 Anatidae. "Ducks, belonging to the鸭科 Phasianidae and the鸭亚科 Anatidae, are commonly recognized as waterfowl, typically found in rivers, lakes, ponds, and marshes. Ducks exhibit distinct physical characteristics such as a small stature, slender neck, and elongated beaks compared to the more robust appearance of swans. Their body shape is characterized by legatively backward placement, similar to the manner in which swans walk. Ducks display variability in vocalizations, ranging from shrill chirps to a versatile range of sounds, particularly noticeable in male鸣叫 and female hatching calls."
This revised version maintains the meaning of the original sentence while incorporating proper grammar and vocabulary for the different parts of speech. The paragraph provides an introduction to the topic of ducks, their classification, and their physical attributes. It also highlights their叫声, particularly emphasizing that they are "duck" in this context, not a specific bird type. The modified text also uses a clear tone throughout, maintaining an objective and informative style. By eliminating unnecessary words and phrases, the revised passage enhances its readability and coherence.