He was only seventeen when he joined the army.

他参军时不过17岁。

《新英汉大辞典》

But I'm only seventeen!

但我只有十七岁啊！

youdao

She's a good girl and she's only seventeen.

她是个好姑娘，今年才十七岁。

youdao

Emperor Norton's decree said John Brown had tried to capture the state of Virginia with only seventeen men.

VOA: special.2009.12.14

Currently,only seventeen states require personal finance to be taught at least as part of other courses.

VOA: special.2009.04.10

Before this project, the language of the Yukagir was spoken fluently by only seventeen people.

UNESCO: CULTURE

By the time McKeon gavelled his meeting to order, just after ten in the morning, only seventeen members of the House Armed Services Committee (five Democrats and twelve Republicans) had shown up to hear the three former heads of the Joint Chiefs of Staff who had been called to testify.

NEWYORKER: The Force

Smartphones are the biggest culprit, though not the only one: seventeen percent of all gamers have downloaded a gaming app for their phone.

FORBES: US Gaming Population Has Almost Tripled Since 2008