The meetings will be held on an ad hoc basis.

会议将根据需要随时举行。

《牛津词典》

"I would accept opportunities in TV on an ad hoc basis," he said.

“在特别需要时我会接受在电视上露面的机会，”他说道。

《柯林斯英汉双解大词典》

For practical purposes, regular expressions need to be handled on an AD hoc basis — and we have grep for just this purpose.

实用起见，规则表达式需要以特殊方式处理——为此我们使用grep。

youdao

Afterward it ran evacuations for Forbes 500 companies and governments on an ad hoc basis.

FORBES: Flight To Safety

But its members have agreed to provide "expertise... on an ad hoc basis", the government says.

BBC: Government wine cellar escapes cost-cutting axe

In the past, that type of coordination happened on an ad hoc basis, an administration official said.

CNN: U.S. government agencies shape cyberwarning strategy