The words with the meaning "majority"
Let's look at the adverbs 大都 and 大多, the adjective 大多数 and the noun 大大部分.
The adverbs 大多 and 大都
The adverbs 大都 
and 大多 have the same meaning "mostly, for the most part".
They are placed before a predicate expressed by a verb, a verb phrase or an adjective.
and 大多 have the same meaning "mostly, for the most part".
They are placed before a predicate expressed by a verb, a verb phrase or an adjective.
Pay attention
In spoken language, 大都 is pronounced as dàdōu.
They are placed before a predicate expressed by a verb, a verb phrase or an adjective.
Examples
小孩儿大都喜欢吃甜的
Most children like to eat sweets
xiǎoháir dàdū xǐhuān chī tián de
参加这次活动的人大都是留学生
Most of the participants in this event are international students
cānjiā zhè cì huódòng de rén dàdū shì liúxuéshēng
他的笑话大多粗俗不堪
Most of his jokes are vulgar
tā de xiàohuà dàduō cūsú bùkān
战斗大多集中在首都北部
The fighting is mainly taking place in the north of the capital
zhàndòu dàduō jízhōng zài shǒudū běibù
The adjective 大多数
The adjective 大多数 is followed by a noun.
is followed by a noun. Pay attention
大多数 is usually followed by the particle 的 .
.Examples
大多数报纸都有政治倾向
Most newspapers have a political slant
dàduōshù bàozhǐ dōu yǒu zhèngzhì qīngxiàng
大多数的现代艺术引不起我的兴趣
Most works of modern art don't interest me
dàduōshù de xiàndài yìshù yǐn bù qǐ wǒ de xìngqù
The noun 大部分
大部分 has the same meaning as the words above.
It can be followed by a noun, a verb or a verb phrase.
has the same meaning as the words above.
It can be followed by a noun, a verb or a verb phrase. Pay attention
A verb phrase is a combination of a verb and an auxiliary word. The auxiliary word can be either an auxiliary verb or an object.
大部分 is often followed by the adverb 都 .
.Examples
我大部分时间都在歌唱爱情
Most of the time I sing about love
wǒ dàbùfen shíjiān dōu zài gēchàng àiqíng
那个湖的大部分都在背阴中
Most of the lake is in the shadow
nà ge hú de dàbùfen dōu zài bèiyīn zhōng