It is unclear how many attackers took part in the assault, how many people have been wounded or killed and how many people remain captive.

VOA: standard.2009.03.30

There has been, over the years a lot of turf battles between the SEC and the CFTC because it's sometimes unclear whether something is a security or a futures.

历年来,证券交易委员会和期货交易委员会的领域战争层出不穷,因为有时候很难说,一个东西究竟是证券还是期货。

耶鲁公开课 - 金融市场课程节选

The Media Club of Afghanistan is blaming NATO forces for the death of their respected colleague, although it remains unclear whether Munadi was shot by the commandos or the Taliban.

VOA: standard.2009.09.10