I do not know whether you realize it, but this condition is essential to us.
我不知道你是否了解,但是,这个条件对我们是必要的。
On the B.B.C. you can hear the clock when it is actually striking because microphones are connected to the clock tower.
当大钟打点的时候,你可以从英国广播公司的广播中听到,因为钟塔上接了麦克风。