1. For they came and went with such frequency that I never even got a chance to learn their names.
    因为他们来匆匆，所以我甚至都没有机会知道他们的姓名。

2. What´s the frequency of this broadcast?
    这广播的频率是多少?

3. This depends on the precise radio- frequency of the 21- cm wavelength, or 1420 megacycles per second .
    这种方法依靠21厘米波长或每秒1420兆周的精确无线电频率。

4. This depends on the precise radio- frequency of the 21- cm wavelength, or 1420 megacycles per second .
    这种方法依靠21厘米波长或每秒1420兆周的精确无线电频率。

5. This depends on the precise radio frequency of the 21-cm wavelength, or 1420 megacycles per second.
    这种通迅联系要靠21厘料波段，即每秒1420兆周的精确无线电频率。

6. The realization hit me that I can expect this kind of personal contact with death to occur with greater and greater frequency.
    我顿时意识到我与死亡的接触会越来越频繁。

7. — Whether because of abandonment, separation, divorce or death of a spouse, marriages are dissolving with increasing frequency.
    ——不论是因为被遗弃、分居、离婚，还是因为配偶死亡，婚姻解体的频率都在上升。

8. Once the existence of this wave-length had been discovered, it was not long before its use as the uniquely recognizable broadcasting frequency for interstellar communication was suggested.
    一旦这种波长的实际存在被发现，提出把它作为星际间唯一可辨认的广播频率就为期不远了。

9. I am interested in audio frequency amplifier.
    我对音频放大器感兴趣。

10. It is the natural frequency of emission of the hydrogen atoms in space .
    这是空间氢原子“释放”的自然频率.