I handed in my paper, leaving the last question blank.

我交了卷子，把最后一个问题留空。

youdao

By using the default attribute, you can leave the parameter in question blank and it is automatically assigned the default value.

通过使用缺省属性，您可以将所讨论的参数保留为空，缺省值将会自动分配到该参数。

youdao

If you can't answer the question, leave a blank.

如果回答不了问题，就空着它。

《牛津词典》

The government says there is no question of taxpayers handing a blank cheque to British Energy.

BBC: Q&A: British Energy's crisis

If participants were asked about their participation as part of the rating process, they were about 1.5 times more likely to admit an ethical misstep than if they were simply asked point blank as a separate question.

FORBES: Use Comic Sans to Get People to Reveal their Most Sensitive Private Information Online

Blank gets the "saturation question" a lot.

FORBES: Magazine Article