词根词缀：a-, ab-, abs-

【来源及含义】Latin: prefix; from, away, away from

【相关描述】This prefix is normally used with elements of Latin and French origins (abs- usually joins elements beginning with c, q, or t).

The form ab- is regularly used before all vowels and h; and it becomes a- before the consonants m, p, and v. The prefix apo- has similar meanings.

This list is a very small sample of the multitudes of a-, ab-, abs- prefixes that are available in dictionaries and those in this unit are only meant to present a few examples.

【同源单词】abampere, abampere centimeter squared, abampere per square centimeter, abarticular, abarticulation, abbreviate

词根词缀：ad-

【来源及含义】Latin: prefix; to, toward, a direction toward, addition to, near, at; and changes to: ac-, af-, ag-, al-, an-, ap-, aq-, ar-, as-, at- when ad- is combined with certain words that begin with the letters c, f, g, l, n, p, q, r, s, and t

【相关描述】The form ad- appears in this form before a vowel and before the consonants d, h, j, m, and v. It is simplified to a- before sc, sp and st.

Before c, f, g, l, n, p, q, r, s, and t; ad- is changed to ac-, af-, ag-, al-, an-, ap-, aq-, ar-, as-, and at-.

In other words, the d of ad usually changes into the same letter as the first letter of the following root or word when it is a consonant: ad-fix becomes affix, and ad-sign becomes assign; therefore, making a double consonant.

Another example includes: attract as with ad-tract (drawn towards); so it has a double t. On the other hand when ad- precedes a vowel, as with adapt, it is simply ad-apt, with one d. For the same reason, there is only one d in adore and adumbrate, because ad- has combined with orare and umbra each of which starts with a vowel.

So, remember: since these Latin words begin with vowels and not consonants, the d of ad does not double as shown in the previous examples.

【同源单词】a capite ad calcem, Ab ovo usque ad mala, Ab uno ad omnes, Abiit ad majores, abjure, accede

词根词缀：jus-, just-, jur-

【来源及含义】Latin: right, upright, equitable; legal right, law

【相关描述】Directly related to the jud-, judic- unit.

【同源单词】abjure, abjure, abjurer, adjuration, adjuratory, adjure