当一个名词用作表语或同位语等表示一个领导职位时，前面常不加冠词（也可说省略掉冠词）：

In 1993 Bill Clinton became (the) President of the United States.

1993年克林顿成为美国总统。

He is still head of the organization.

他仍然是这个组织的首脑。

This is Professor Brockbank, head of the history department.

这是历史系主任布洛克邦教授。

He succeeded his father as president of the company.

他接替他父亲担任公司董事长。

This is Mr. Kirk, director of the Department of African Affairs.

这是非洲司司长科克先生。

They appointed him minister to a foreign country.

他们任命他为驻外公使。

尽管指普通员工，某些职务名称前也有不加冠词的趋势：

I'm coming back to take the job of foreign editor.

我将回来当外语编辑。

She worked as correspondent to a local newspaper.

她担任当地一家报纸的记者。

在turn后的表语都不带冠词：

He was a Conservative but he turned Socialist.

他原是保守党员后来成了社会党人。

He has turned botanist (Mahammedan).

他成了植物学家（回教徒）。

在title和rank后，名词前也多不带冠词：

I prefer the title of reporter.

我更喜欢记者的头衔。

That officer holds the rank of captain.

那位军官的官阶为上尉。