1. There are only a limited number of broadcasting frequencies. 只有数量有限的广播频率。
2. It's easier to find and acquire jamming equipment for some frequencies than it is for others. 某些频率比其他频率更容易找到并获取干扰设备。
3. The young of ground-nesting warblers produce begging cheeps of higher frequencies than do their tree-nesting relatives. 相比在树上筑巢的同种类雏鸟，在地面筑巢的鸣禽雏鸟会发出频率更高的乞食叫声。
4. Keyssar rightly understands that a better way to measure the impact of unemployment is to calculate unemployment frequencies. Keyssar 正确地认识到，衡量失业影响的更好的方法是计算失业频率。
5. Much of the money in this project is being spent on developing the special hardware needed to search many frequencies at once. 这个项目中的很多资金都用在研发所需的能同时搜寻多个频率的特殊硬件上。
