Subject only one, namely, the pursuit of perfection.

主题只有一个，即追求完美。

youdao

But each subject can only belonged to one subscription.

但是，每个主题只能属于一个订阅。

youdao

A subject contains many documents, but each document can only belong to one subject.

一个主题可以包含很多文档，但是每个文档只能属于一个主题。

youdao

Mister Riordan says there was only one subject that amazed his students more than ancient Greece and that was ancient Egypt.

VOA: special.2009.10.12

In one respect it is even more extensive and demanding: AP classes are typically in one subject, targeted at only the best high school students, and designed to produce maximum results on a single year-end SAT test.

FORBES: Testing California's Commitment to Education

Every commitment to an idea is ultimately subject to forfeit to the exigencies of the moment, if only one puts on the perfunctory public showmanship about fighting and resisting first.

FORBES: William Kristol's Acceptance Of The Mess Is Wholly Unacceptable

Of course, this study is subject to the caveats that it: (a) only involved one decision making task and (b) only involved undergraduate students.

FORBES: Have a Tough Decision to Make? Science Says: 'Sleep On It!'