主格（The Nominative Case）[编辑]
凯萨是罗马的皇帝（Caesar is emperor of Rome.）
凯萨的军队进入了罗马（Caesar's army entered Rome）
|magn-us -a -um||棒|
|bon-us -a -um||好|
|mal-us -a -um||坏|
|puell-a -ae (f.)||女孩|
|ambula-t, ambula-nt||(他/她/它) 正在走路, (他们/她们) 正在走路|
|curri-t, curru-nt||(他/她/它) 正在跑步, (他们/她们) 正在跑步|
|有些雄性名词的第二变格（declension ），不是以-us结尾，而是以 -r — 像男孩的第二变格是puer，不是puer-us。在这一页的单字里面，只有puer符合这个状况。|
- m. = 雄性
- f. = 雌性
- n. = 中性
- First and second declension substantives are given with at least the nominative case. (We will add the genitive singular as time permits. It is not strictly necessary, but you should get in the habit now of declining nouns based on the genitive stem and not the nominative. This chapter is therefore slightly misleading in this regard.)
- Third, fourth, and fifth declension substantives are given with the nominative and genitive singular.
|The good boy walks. （这个好 男孩在走路。）||Puer bonus ambulat.|
形容词也可以用在使用be动词的句子里面。be动词仅仅是一个连接性的动词（注：英文文法里面，句子里面一定要有动词），“好男孩”（"the good boy"）文法上不是一个完整的句子，但是“这男孩是好的”（"the boy is good"）就是一个完整的句子了。
|这男孩是 好的.||Puer bonus est.|
跟名词一样，拉丁文的形容词也是用字尾修饰。大部分形容词使用第一种或者第二种词尾（antiquus -a -um，古老的）有时使用第三种词尾（ferox, ferocis，激烈的）。 这类形容词必须与所形容的名词使用相同的性别、时态、格式，但是不一定是相同词尾。
- First and second declension adjectives have three distinct genders. Feminine adjectives require the first declension, masculine the second, and neuter the second. First/second declension adjectives use all three gender suffixes: -us, -a, -um (masculine, feminine, and neuter, respectively). This is because description is not limited to a single gender. For example, being good is not a quality limited to a single gender. Boys can be good, girls can be good, and things can be good. So, since all three genders must apply, we don't label adjectives as particularly m., f., or n..
- Third declension adjectives are given with the nominative and genitive singular. This, however, is only true for third declension adjectives of one termination, so again this chapter is misleading in this regard. Most third declension adjectives do not have separate masculine and feminine forms. (Neuter adjectives follow the third declension neuter pattern.)
这些形容词像是 antiquus (老的，陈旧的):
- antiquus (雄性), antiqua (雌性), antiquum (中性).
Third declension adjectives typically look more like ferox, ferocis (wild, bold). This is because the third declension has no stem assigned to the nominative singular and is a "wild card" in that regard.
Adjectives often come after the word they describe. (But since word order is not central to the meaning of a Latin sentence, the adjective may appear anywhere within the sentence. In poetry, for example, several words often separate an adjective from the noun it modifies.)
For example: Nota bene: In the following examples the -us ending stands for the masculine (m.) gender, the -a for the feminine (f.) gender, and the -um stands for the neuter (n.) gender. So magnus is masculine, magna is feminine and magnum is neuter.
|Puella bona est.||The girl is good.|
|Dominus bonus est.||The master is good.|
|Templum magnum est.||The temple is big.|
Bona is an adjective describing a feminine substantive, such as puella.
Bonus is an adjective describing a masculine substantive, such as dominus.
|个数||第一词尾 雌性||第二词尾 雄性||第二词尾 中性|
To pluralize most first and second declension nouns, replace the singular suffix with the equivalent plural suffix. All adjectives that describe the noun must be pluralized as well because adjectives must agree in case, number, and gender (but not necessarily declension). With the adjectives given, use first declension with feminine nouns and second declension with masculine nouns. In English we use the same nominative plural endings for words we have borrowed from Latin, so it may be helpful to remember we say one vertebr-a but two vertebr-ae, one radi-us but two radi-ī, and one medium but multi-medi-a.
Verbs in Latin work quite differently than those in English. Study the following table, then view the examples below, though keep in mind that you only need to fully understand the difference between numbers for the time being.
|Number||Only pluralize the noun that is being pluralized, not the adjectives that describe it or the verb that it is performing.||All three are pluralized. In this context, singular verbs end in "-t" (est, ambulat), and plural verbs end in "-nt" (sunt, ambulant).|
|Tense||The ending is sometimes changed, though the words surrounding the verb can also be used to denote tense. Consider these examples: "he will walk, he is walking, he walks, he walked".||The stem is used to denote the tense, though this will be covered in a future lesson. In this lesson, only the present tense is being taught.|
|Person||The subject of the sentence is used to determine the person. If I am the subject of the sentence, then the sentence is in the first person. If you are the subject, then the second person, and so forth with the third. In this lesson, only the third person is being taught, which refers to anyone other than the speaker or the listener.||The stem also denotes the person, though as previously stated, only third person is being taught in this lesson.|
|puell-a bon-a es-t.||The girl is good.|
|And to pluralize:|
|puell-ae bon-ae su-nt||The girls are good.|
|Note that verbs do not have gender, in that they do not change to the gender of the word that they are describing.|
|Puer bon-us ambula-t.||The good boy is walking.|
|And to pluralize:|
|Puer-ī bon-ī ambula-nt||The good boys are walking.|
|You will notice that neither the linking verbs "est" nor "sunt" appear in the previous two sentences. The meaning of the linking verbs are assumed in Latin sentences, as their respective meanings already exist in the verb stems.|
|triclīni-um magn-um es-t||The dining room is large.|
|And to pluralize:|
|triclīni-a magn-a su-nt||The dining rooms are large.|
|templum magnum est||The temple is big.|
- 形容词 magnus -a -um 与 templum 必须要同性别、同个数（单/复）、同时态。and case, so the correct form is magnum (neuter nominative singular).
- Something like templum magnus est is incorrect because magn-us does not agree with templ-um. To a Latin speaker, this would sound like nonsense.
|puella magna est.||The girl is big.|
Notes: In the same way, the adjective magnus -a -um must agree with puella in gender, number, and case, so the correct form is magna (feminine nominative singular, a-declinatio).
|Puer currit.||The boy is running.|
|Puerī currunt.||The boys are running|
Notes: You may notice that, when pluralized, "currit" becomes "currunt". The original spelling was probably "currint", but changed to "currunt" over time to make it easier to say. This is true of any pluralized verbs that would otherwise be ending in "-int".
|lūdī magnī sunt||The schools are big.|
Notes: The adjective magnus -a -um in this case must agree with lūdī in gender, number, and case, so the correct form is magnī (masculine nominative plural).
Third declension nouns and adjectives follow a different pattern. The nominative singular stem is not defined, and as such, any letter (or letters) can serve as a third declension stem. For example, Māter (mother) is a third declension noun in the nominative case. When pluralized, it becomes Mātrēs. "-ēs" is attached to the end of a third declension noun to pluralize it, as opposed to changing the ending completely, because there is no uniform way to do so given the third declension's random nature.
You may have also noticed that that the "e" in "Māter" was dropped when pluralized. This often happens when a stem is attached to a third declension noun of similar spelling (example, "Pater" (father) becomes "Patrēs")
|māter bona est||The mother is good.|
|mātrēs bonae sunt||The mothers are good.|
|pater magnus est||The father is large.|
|patrēs magnī sunt||The fathers are large.|
|amīcus fortis est||The friend is strong.|
|amīcī fortēs sunt||The friends are strong|
Third declension nouns are listed with the nominative case and the genitive case to provide the main stem, which will be covered in a few lessons. All other nouns are also listed with the genitive for standardization, but often just the genitive ending is given. For example:
All other types of nouns are also generally listed with the genitive
Adjectives with a nominative ending in -is and the same stem in the nominative and in the other cases (eg. fortis) end in -e in the neuter and -ia in the neuter plural.
- dies difficilis = the difficult day
- proelium difficile = the difficult battle
- proelia difficilia = the difficult battles
- dominus bonus
- lūdus malus
- puella magna
- trīclīnium est magnum
- Puer bonus
- dominus magnus
- templum magnum est
- dominus malus est