Wǒ yì tīng, wǒ jiù míngbái le.
False: 我一听,我就明白了。
Wǒ yì tīng, wǒ míngbái le.
True: 我一听,我明白了。
英语可以说I got the idea as soon as I heard it。在汉语里,因为“一……就……”连接两个紧接着发生的动作,前后两个分句的主语用词重复,应该删去第二个“我”。
In English, it is perfect to say "I got the idea as soon as I heard it". However in the Chinese fixed pattern 一……就…… which joins two events in quick succession, only one among the two clauses requires a subject. 我 in the second clause should be erased.