* 本文属于《满庭说英语》中《简简的语法》系列，每一篇都用短短的篇章精讲英语语法中的各个要点和有意思的知识点。《满庭说英语》的特点都是用英语来理解英语为主，适度辅以少量中文解说，帮助英语学习者建立英语思维、深入了解英语的内涵。
* 解析中英语单词的音标使用Dictcom和IPA双音标标注，如果需要了解Dictcom音标，请参看我们的《dictionary.com所用的音标体系》一文。
* 本篇文章难度系数5.8，由《小仙英语伴读》人工智能难度分析系统提供评分。
#英语#
【编者按】不定式（infinitive）是英语中动词的一种特殊形态，我们一般的理解是：通过在动词原形前加上“to”，将其转换为具有名词性特质的短语，但又保持了一些动词的特性，例如可以加副词修饰等。但其实不定式主要是指动词的形式“不限定”，也就是不做任何变型，即总是使用动词原形。英语中将不包含前面的“to”的不定式（动词原形）称为bare infinitive，直译可以译作“裸”不定式；而带有前置“to”的不定式则称为full infinitive，直译为“全”不定式。不定式最大的特征就是动词无论如何都保持原形，不会有任何变形。不带to的不定式最典型的例子就是在情态动词后，例如：We will go tomorrow. 这里的动词go不会有任何形变。
【又注】从infinitive这个词的由来也可以看出：finite是“有限的”、“限定的”意思，infinite是“无限的”、“不加限制的”，infinitive则是由infinite变化而来专指动词不定式的名词。
Two classes of verb-forms illustrate in a striking way the fact that the same word may belong to different parts of speech; for they really belong to two different parts of speech at one and the same time.【译】两类动词形式令人惊异地说明了同一个词可能属于不同的词类，因为它们确实是同时属于两个词类。【单词】illustrate ['il-uh-streyt, ih-'luhs-treyt]['ɪləstreɪt] vt. 说明；图解 vi. 举例说明【单词】striking [ˈstraɪkɪŋ] adj.引人注目的; 异乎寻常的; 显著的【单词】belong [bih-'lawng, -'long][bɪ'lɒŋ] vi. 应归入；属于【单词】speech [speech][spiːtʃ] n. 演说；演讲；言语；语言能力
These are the infinitive (which is both verb and noun) and the participle (which is both verb and adjective).【译】它们是不定式（既是动词又是名词）和分词（既是动词又是形容词）。【单词】infinitive [in-'fin-i-tiv][ɪn'fɪnətɪv] n. 不定式【单词】verb [vurb][vɜːb] n. 动词【单词】noun [noun][naʊn] n. 名词【单词】participle ['pahr-tuh-sip-uhl, -suh-puhl][pɑː'tɪsɪpl] n. 分词【单词】adjective ['aj-ik-tiv]['ædʒɪktɪv] n. 形容词
Examples of the infinitive may be seen in the following sentences:【译】不定式的例子可以在以下句子中看到：【单词】following 原型：follow ['fol-oh]['fɒləʊ] v. 跟随；追赶；紧接着【单词】sentences 原型：sentence ['sen-tns]['sentəns] n. 句子
To struggle was useless.【译】挣扎是没有用的。【单词】struggle ['struhg-uhl]['strʌɡl] vi. 努力；奋斗；斗争；挣扎【单词】useless ['yoos-lis]['juːsləs] adj. 无用的；无效的
To escape is impossible.【译】逃跑是不可能的。【单词】escape [ih-'skeyp][ɪ'skeɪp] v. 逃跑；逃脱；逃避【单词】impossible [im-'pos-uh-buhl][ɪm'pɒsəbl] adj. 不可能的；做不到的
To exercise regularly preserves the health.【译】有规律地运动有助于保持健康。【单词】exercise ['ek-ser-sahyz]['eksəsaɪz] vi. 锻炼【单词】regularly ['reg-yuh-ler-lee]['reɡjələli] adv. 有规律地；定期地【单词】preserves 原型：preserve [pri-'zurv][prɪ'zɜːv] v. 保护；保存；保持
To struggle is clearly a noun, for (1) it is the subject of the sentence, and (2) the noun effort or exertion might be put in the place of to struggle.【译】to struggle显然是名词性的，因为（1）它是句子的主语，（2）可以用名词“effort”或“exertion”代替“to struggle”。【单词】effort ['ef-ert]['efət] n. 努力；努力的成果【单词】exertion [ig-'zur-shuhn][ɪɡ'zɜːʃn] n. 努力；发挥；运用
Similarly, the noun escape might be substituted for to escape; and, in the third sentence, regular exercise (a noun modified by an adjective) might be substituted for to exercise regularly.【译】同样地，名词escape替换掉to escape；在第三句中，可以用regular exercise（由形容词修饰的名词）来代替 to exercise regularly。【单词】Similarly 原型：similarly 副词 ['sim-uh-ler]['sɪmələli] adv. 相似地；类似地【单词】substituted 原型：substitute ['suhb-sti-toot, -tyoot]['sʌbstɪtjuːt]vt. 代替；用 ... 代替；代以【单词】regular ['reg-yuh-ler]['reɡjələ] adj. 有规律的；定期的；经常的；规则的【单词】modified 原型：modify ['mod-uh-fahy]['mɒdɪfaɪ] v. 修改；更改；缓和；修饰
【解析】escape可以做名词，而在不定式to escape中的escape则是动词，所以这里说escape可以代替to escape。
But these three forms (to struggle, to escape, and to exercise) are also verbs, for they express action, and one of them (to exercise) is modified by an adverb (regularly).【译】但这三种形式（to struggle, to escape, 和to exercise）也是动词，因为它们表示动作，其中一种（to exercise）由副词（regularly）修饰。【单词】express [ik-'spres][ɪk'spres] vt. 表达；表示【单词】adverb ['ad-vurb]['ædvɜːb] n. 副词 adj. 副词的
Such forms, therefore, are noun-forms of the verb.【译】因此，这些形式是动词的名词形式。
They are classed with verbs, and are called infinitives.【译】它们分类上被分为动词，叫做不定式。【单词】infinitives 名词复数形式 infinitives n. 不定式（infinitive的复数）
The infinitive is a verb-form which partakes of the nature of a noun.【译】不定式是一种具有名词性质的动词形式。【单词】partakes 原型：partake [pahr-'teyk][pɑː'teɪk] vi. 参与；分担；分享；颇有 vt. 参与
It is commonly preceded by the preposition to, which is called the sign of the infinitive.【译】它通常在介词前面，这被称为不定式的符号/标志。【单词】commonly ['kom-uhn-lee]['kɒmənli] adv. 一般地；通常地；普通地【单词】preceded 原型：precede [pri-'seed][prɪ'siːd] vt. 在 ... 之前；先于 vi. 在前面；领先【单词】preposition [prep-uh-'zish-uh n][ˌprepə'zɪʃn] n. 介词【单词】sign [sahyn][saɪn] n. 手势；招牌；符号
The infinitive without to is used in a great variety of verb-phrases.【译】而不带“to”的不定式被用在各种动词短语中。【单词】variety [vuh-'rahy-i-tee][və'raɪəti] n. 多样；种类；多样化
I shall go.【译】例如：我要走了。
John will win.【译】约翰会赢的。【单词】win [win][wɪn] v. 赢；赢得；获胜；获得 n. 胜利【专有名词】John 人名/人物 [jon][dʒɒn] n. 约翰(男子名)
Mary may recite.【译】玛丽可以背诵。【单词】recite [ri-'sahyt][rɪ'saɪt] vt. 背诵；朗诵；叙述；列举 vi. 背诵；回答问题【专有名词】Mary ['mair-ee]['mɛəri] n. 玛丽（女子名）
Jack can swim.【译】杰克会游泳。【单词】swim [swim][swɪm] v. 游泳 n. 游泳【专有名词】Jack [jak][dʒæk] n. 杰克（男子名）
Such phrases will be studied in connection with the inflection of verbs.【译】这些短语将结合动词的音调变化来研究。【短语】in connection with 与……有关；与……相连；例句：It is better to express your anger, rather than bottle it up. 生气宁可发泄出来而不要闷在肚内。【单词】phrases 原型：phrase [freyz][freɪz] n. 短语；习语；措辞【单词】connection [kuh-'nek-shuhn][kə'nekʃn] n. 联系；关系【单词】inflection [in-'flek-shuh n][ɪn'flekʃn] n. 变调；音调变化
Note.【译】注意。
That go, win, recite, and swim are infinitives may be seen by comparing the following sentences:—"I intend to go," "John is sure to win," "Mary is permitted to recite," "Jack is able to swim."【译】上面的例句中go、win、recte和swim是不定式，通过比较以下句子可以看出：——“I intend to go （我打算去）”，“John is sure to win（约翰肯定会赢）”，“Mary is permitted to recite（玛丽可以背诵） ”，“Jack is able to swim（杰克会游泳）。”【固定用法】be able to do sth. 能够，会(做)；有能力(或办法、机会)做某事；例句：I am able to pick you up on the short wave radio. 我能用短波收音机收听到你的信号。【用法】be sure to do sth. 表示“肯定会做某事”，有确信的意思。例如：I'm sure that Tom lives here. 我确信汤姆住在这里。【用法】tend to表示“朝某方向；趋向；偏重”，后面接动词原形。如：We tend to make mistakes when we do things in a hurry.忙中不免出错。【单词】comparing 原型：compare [kuh m-'pair][kəm'peə] v. 比较；对比；比喻【单词】intend [in-'tend][ɪn'tend] vt. 想要；打算；意指【单词】permitted 原型：permit [per-'mit][pə'mɪt] v. 允许；许可
,
