Names of people, places and organisations are called proper nouns. We spell proper nouns with a capital letter:
人名、地名、组织名称都是专有名词。开头首字母要大写。

Mohammed Ali; Birmingham; China; Oxford University, the United Nations

We use capital letters for festivals:
节日名称的首字母也要大写：

Christmas; Deepawali; Easter; Ramadan; Thanksgiving

We use a capital letter for someone’s title:
某人的特定称谓的首字母也要大写：

I was talking to Doctor Wilson recently.

Everything depends on President Obama.

When we give the names of books, films, plays and paintings we use capital letters for the nouns, adjectives and verbs in the name:
书名、电影名、戏剧名和画作名称，首字母都要大写：

I have been reading ‘The Old Man and the Sea’.

Beatrix Potter wrote ‘The Tale of Peter Rabbit’

You can see the Mona Lisa in the Louvre.

Sometimes we use a person’s name to refer to something they have created:
有时候我们用某人的名称代表他们所发明的事物：

Recently a Van Gogh was sold for fifteen million dollars.

We were listening to Mozart.

I’m reading an Agatha Christie.