n.先買（權(quán)）；先占

However, the denial made little effect in eliminating the preemption. 然而，國家法律的否定對改變民間交易中的先買權(quán)習慣收效甚微。

Of these, the way of imposing had great influence on the existence of the preemption. 對先買權(quán)而言，影響最大的就是國家的稅糧征收方式。

One controversial preemption issue involves nuclear energy. 一個有爭議性的先占權(quán)問題也涉及到了核能。

This reluctance to infer preemption makes sense, because the agency can readily adopt an express preemption regulation. 這種不愿意使用先占權(quán)的做法是有意義的，因為機構(gòu)能隨時采用明確的先占權(quán)法令。