您要查找的是不是：
- They netted the fruit trees to protect them from birds. 他们用网覆盖住果树以使其免遭鸟害。
- He varied the transmission frequency. 他变换了无线电传送的频率。
- These rare tigers are protected by special laws. 这些珍贵的老虎受到专门法律的保护。
- The computer is protected by a plastic cover. 计算机得到塑料套的保护。
- The data stored in a computer can be protected. 存储在计算机里的数据能被保护起来。
- A unit of frequency equal to one cycle per second. 赫兹频率的单位，等于每秒一周
- How can we protect our computer files? 我们怎样才能保护我们的计算机数据？
- The plants should be protected against the cold. 应该保护这些植物使之不受冻。
- The plants should be protected from the cold. 应该保护这些植物使之不受冻。
- His body was protected by armour fore and aft. 他的身体前前後後都有盔甲保护。
- Fatal accidents have decreased in frequency over recent years. 近年来死亡事故发生的频率已经下降。
- A plastic cover protect the computer. 这台计算机由一个塑料防护罩盖着。
- It's our duty to protect the saplings. 保护树苗是我们的责任。
- We can often correlate age with frequency of illness. 年龄的大小往往与发病率有关。
- The perimeter of the airfield is protected by guard-dogs. 机场外的环形防卫圈由警犬保卫着。
- Accidents on that highway are happening with increasing frequency. 那条高速公路上车祸发生得越来越频繁。
- In case of flood, the dam can protect us. 在发洪水的时候，大堤可以保护我们。
- A law was passed to protect alien property. 通过了一项法律保护外国侨民的财产。
- An umbrella will protect you from the rain. 雨伞可以保护你不致雨淋。
- These policemen wear helmets to protect them. 这些警察戴着头盔保护自己。
