英美法系又称英吉利法系、普通法法系，是以英国法为基础，兼以衡平法和普通法为主要渊源，融合教会法和商人法，吸收若干罗马法的原则和制度而形成的世界性法律体系。（）
A、对
B、错
I. (Legal History)The elements of vertical pluralism were supplemented with structures of horizontal pluralism through their adherence to the idea of a ius commune (普通法). The Lombard libri feudorum (a twelfth century collection, originating in Lombardy, of feudal customs, which gained wide acceptance as a statement of the various rules governing the relation of lord and vassal.), the main source of feudal law, had early on become a part of the Corpus iuris civilis (民法); and while Canon law maxims were applied also in the context of the Roman ius commune, Canon law included substantial elements of Roman law. Here, the general principle was: ecclesia vivit leg Romana (教会的罗马法). Similarly, the lex mercatoria (商人法) was not a fully independent body of transnational commercial law, but rather consisted of many, mostly local, norms that modified Roman law in matters of commercial practice. Normally, the decisions of the merchants’ courts were based on the ius commune, which was indeed regarded as the “mater legis mercatoriae”（商人法之母）. The Roman rules were only modified in accordance with the needs of commerce on the basis, for example, of the idea of an aequitas mercatoria (商人的正义). Altogether, this was a complex system with rules both conflicting with and complementing each other. For instance, the relationship between Canon law and the secular ius civile (世俗民法) was never without tensions. Indeed, the idea of a ius coinmune was in itself a plural one: the ius commune was based on a range of different legal sources and it integrated two independent legal systems, namely the mundane Roman law on the one hand and the Canon law of the Roman Church on the other hand. For a medieval jurist, the Decretum Gratiani (a collection of Canon law compiled and written in the 12th century as a legal textbook by the jurist known as Gratian) and later collections of Papal legislation were as important sources of the ius commune as the roman Corpus iuris civilis. In addition, these texts were complemented with the Emperor’s legislation (at least within the confines of the Old Empire), with the authoritative Glosses (commentaries) to the corpora iuris Romani (罗马法) and Canonici (as it was later called), and later also with the principles of Natural Law.51. The Lombard libri feudorum is ___.52. According to the author, the lex mercatoria ___.53. Which of the following statement is closest in meaning with the underlined sentence?54. Which of the following is NOT mentioned as the important source of the ius commune in the paragraph?
国际贸易法的发展，大致经历了以下哪几个时期（）
A、商人法的产生
B、经济法的兴起
C、民商法的兴起
D、国际贸易法的统一化
简述中世纪的商人法的特点是什么？（中财2011年研)