CNN 《Company Uses Drones In
Reforestation》There's multiple drones operating to perform a task simultaneously.这里的operating怎么理解？其后的to perform是作名词定语，还是表目的呢？
...after decades of development and construction, and it thrilled astronomers when it successfully unfolded itself out in space.所以这里为什么要用主动语态呢？不应该是望远镜被发射吗？