1.precede v.在…之前，早于（to be earlier than）

词根记忆：pre(前)+cede(走)--走在前面--在…之前

例：Leibniz' notes are limited to early sections of Newton's book, sections that precede the ones in which Newton's calculus concepts and techniques are presented.

同根词：precedent(n.先例：a．在前的)

2.precedence n.优先，居先(the fact of preceding in time)

词根记忆：pre(前)+ced(走)+ence--走在前面--优先

例：The water rights of the inhabitants of the Fort Berthold Indian Reservation would not take precedence over those of other citizens.

同根词：precedential(a．有先例的)

3.preceding a．在前的( to surpass in rank, dignity, or importance)

词根记忆：来自precede(v.领先，在…前面)

例：Present information contradicts the preceding paragraph.

同根词：precedent(a．在前的；n．先例)

4.precipitate v.加速，促成(to bring about abruptly; hasten)a.鲁莽的(impetuous)

词根记忆：pre(预先)+cipit(落下)+ate--先落下了--加速

例：However, since humans tended to migrate to areas as the climate in those areas began to warm, the extinctions might have been precipitated by the climatic warming rather than by human migration.

派生词：precipitation(n．沉淀；沉淀物)

5.precipitation n.沉淀（the quality or state of being precipitated）；沉淀物(sth. precipitated)

词根记忆：来自precipitate(v.使…沉淀；促成)

例：The continental United States receives an average of 30 inches of precipitation a year.

同根词：precipitant(n．沉淀剂)

6.precise a．准确的，精确的(exact)；严谨的（strict）

词根记忆：preci(价值，价格)+se--定价一般都很精确--准确的，精确的

例：The witness gave a precise account of the murder.//precise statement严谨的陈述

派生词：precision[n.精确，精密（度）]

7.precursor n．先驱;先兆;前身(forerunner, predecessor,a substance from which another substance is formed)

词根记忆：pre(前)+curs(跑)+or--跑在前面的人--先驱

例：Lightning is a precursor of thunder.

8.predate v.居先，早于(antedate)

例：Some North American sites of human habitation predate any sites found in South America.