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 instance, perhaps the same Capability type can be associated with one or more unit type on AD hoc basis.

比如，可能由于特别的原因，同一个Capability类型可以与一个或者多个单元类型相连接。

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

Review of systems access procedures, for example, moved from an ad hoc basis to every 90 days.

FORBES: Security