A permit is required to visit, few linguists have worked there and a reliable list of languages has never been drawn up.

由于进入该地区需要官方的许可，只有很少的语言学家在这个地区工作，而且关于这一地区的语言从未形成一个可靠的清单列表。

youdao

The foreign visitor received a special permit to visit this factory.

那位外国旅游者得到了参观这座工厂的特许。

youdao

I have just read that it is now necessary for foreigners to get a permit to visit both Bayanbulak and Karakul Lake.

我刚看到现在外国人必要取得许可证才能去巴音布鲁克草原和卡拉·库尔湖。

youdao

Later a transport system was added to permit people to visit an observation area inside the top of the arch.

VOA: special.2009.03.04

Journalists or other outsiders wanting to visit Wadi Khaled have to first get a permit from the Lebanese army - though don't expect any protection when you are there from them.

BBC: Syria conflict: The Lebanese town living under fire

Syria decided to permit the two-day planned visit.

CNN: McCain calls for airstrikes on Syria