It's these higher frequencies that are clear and static-free.
即超高频。这三种较高的频率很清晰，可不受天电干扰。
2
Cotton clothes don't require fabric softener to stay soft and static-free.
全棉的衣服不需要柔软剂来保持柔软，且它们不会有静电。
3
In order to strengthen the stability and reliability of the system, lightningproof and static-free protection is improved and power trip protection circuits are added to to the design of senor power.