将下列句子译成汉语,注意句中有些冠词的特殊位置: 1. In this case the current (电流) exists for only half the cycle (周期) . 2. In such a case there is no current flowing in the circuit (电路) . 3. Sensitivity (灵敏度) is a measure of how small a signal (信号) a receiver (接收机) can pick up and amplify (放大) to a level useful for communications. 4. ε may be as small a positive constant as you please. 5. Even so fundamental a dimension ( 量纲 ) as time was measured extremely crudely with sand and water clocks hundreds of years ago. 6. Nonlinear distortion ( 非线性失真 ) can be caused by too large an input signal. 7. The method used is quite an effective one. 8. A series (级数) solution of this kind of problem allows as close a calculation of the error as needed.