The obligation is to pay patent application fee every year.

义务就是每年都要缴纳专利申请费。

youdao

Paying or not paying patent annual fee is in nature a kind of legal fact, rather than fulfilling or offending demeanours of legal obligation.

缴纳专利年费的行为或者不缴纳专利年费的行为的性质都是法律事实，而不是履行或者违反法定义务的行为。

youdao

The client must pay the fee (obligation) and is entitled to get the product (benefit).

客户必须付款（任务），并且有权获得产品（权力）。

youdao

He said the BBC had an obligation to ensure value for money for licence fee payers, and a fair and reasonable resolution was needed.

BBC: Vinyl record on turntable

The BBC maintains that it has an obligation to ensure value for money for licence fee payers, and a fair and reasonable resolution was needed.

BBC: A radio presenter at her console