The caudal peduncle is very slender and includes three sets of keels.

尾端的花梗很细，包括三组龙骨。

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As only a very general rule, most sailboats over 20-something feet have fixed keels.

作为一条通常规律，大部分20英尺以上的帆船使用固定龙骨。

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Sailboats have many different types of fixed keels, such as full keels (see photo) and fin keels.

帆船有许多种不同类型的固定龙骨，例如全龙骨(见上图)及鳍板。

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That gives the advantage to multihulls, which are inherently faster and lighter than monohulls, with their heavy lead keels.

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His girlfriend makes him go to a hypnotherapist, who puts him into deep relaxation and then promptly keels over from a heart attack.

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Then it keels over, hissing and gasping as it goes.

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