More research will be needed before we are sure how infra - sound can be used.
我们必须进行更多的研究才会确切地知道如何可能利用亚声。
2
More research will be needed before we are sure how infra-sound can be used.
我们必须进行更多的研究才会确切地知道如何可能利用亚声。
3
NOTE An infra-red control by itself is not considered one used for remote operation. However, it may be incorporated as part of a system such as a telecommunication, sound control or bus system.