III. Translate English into Chinese:把下列句子翻译成中文 1. An electric circuit is an interconnection of electrical elements. 2. Electric current is the time rate of change of charge. 3. Voltage (or potential difference) is the energy required to move a unit charge through an element, measured in volts (V). 4. Power is the time rate of expending or absorbing energy, measured in watts (W). 5. The power absorbed or supplied by an element is the product of the voltage across the element and the current through it. 6. Energy is the capacity to do work, measured in joules (J). 7. The total power supplied to the circuit must balance the total power absorbed.