在句子中充當除謂語以外的句子成分的動詞形式叫作非謂語動詞。非謂語動詞分為三種形式∶動名詞，不定式和分詞。
(一) 分詞
現在分詞和過去分詞的區別
①、用於句首作狀語，現在分詞表示主動，過去分詞表示被動
例：Won its war for independence in 1783, the United States then
A
struggled to establish its own economic and financial system.
B C D
分析：分詞作狀語，主要看是主動還是被動，美國贏得應該是主動,所以A錯，改won為winning
②、用於名詞後面作後置定語，現在分詞表示主動，過去分詞表示被動
例：In the nineteenth century the Mohave Indians lived in
A B
the Northern Hemisphere grew their crops on river bottom lands.
C D
分析：B錯，生活在什麼地方的人，人生活是主動，因此改為living
一些動詞後面必須用doing
對於加doing的詞來說，考試中一般出現一個，下面這些詞都是要加doing的，請考生牢記。
mind, finish, enjoy, celebrate, adjust
advocate, suggest
delay, quit
forgive(原諒)，tolerate，
avoid, escape(逃避)
spend+名詞+doing;
have trouble/difficult/a problem/ +doing
例：Long before the dawn of recorded history, humans celebrated to harvest their
A B C D
crops.
分析：D錯，應改為harvesting。及物動詞celebrate直接帶名詞、名詞短語或動名詞短語作賓語，故將to harvest改為harvesting。
例：Some experts have advocated to bring that country into the talks,
A B
to revive the intermittent dialogue that began after the 1967 Middle East War.
C D
分析：A錯，advocate 後面直接跟doing, 改為advocate bringing
(二) 不定式
A. 動詞不定式的省略
①、help後面可以省略to
help to do
help sb. to do
例：A good exercise program helps teach people to avoid
A B
the habits that might shorten the lives.
C D
分析：D錯，應改為their. 定冠詞在句中不如代詞所有格明確，如果lives後面有定語就可以用the。注意(A)並沒有錯，help後面可以接不帶to的不定式。
②、使役動詞後面要省略to, 這樣的動詞只有三個
make,
let,
have sb. do sth
注意get不是使役動詞，get sb. to do sth.
例：A conductor used signals and gestures to let the musicians
A B
to know when to play various parts of a composition.
C D
分析：let是使役動詞，後面不需要to, C改為know
③、感官動詞
hear, feel, watch, see, notice, observe
see sb do sth. 強調過程
see sb doing sth 正在做某事
B. 動詞不定式的固定用法
(1)表示第一人
the first woman to do sth.
(2)表示迫使的動詞
一般考三個， allow/ enable/ call, +sb. + to do
例：Besides providing clues to the nature of atoms, mineral analysis
A B
allows to speculate geologists about the ancient Earth.
C D
分析： do是固定短語,allow的賓語應在不定式之前,即把C改為: allow geologists to speculate。
(3)表示傾向…的形容詞
be more likely to do 更有可能作某事
be inclined to do傾向於做某事
be liable to do 易於…的
be apt to do
(4)表示目的的名詞，一共有7個這樣的.詞，這一條也是最重要的。
固定的句式：
the purpose , the purpose of sth is to do sth.
the objective 目標
aim
goal
reason理由
function功能
intension意圖
例：The function of Louis Sullivan's architecture was providing
A
large uninterrupted floor areas and to allow ample light into the interior.
B C D
分析：the function to provide, A錯
例：The chief goal of biochemistry is for understanding the structure
A
and behavior of the carbon-containing compounds
B
that make up various components of a living cell.
C D
分析：the chief goal is to understand, A錯
(5) 其他同根名詞
ability to do 受到be able to 的影響
attempt to do 企圖
decision to do 決定, 受decide的影響
ambition,
be ambitious to do
