protected switch

例句：

1. 1. The baby is protected by a soft blanket.
   婴儿被一条软毯子保护着。
2. 2. The treasure was protected by a secret code.
   宝藏被一个秘密代码保护着。
3. 3. The forest is protected by national parks.
   森林由国家公园保护着。