before until的转换
他是对抗菌物质进行了长达九年的实验才有所发现的.两种翻法：1,He experimented with antibacterial substances as long as nine years before he made his discovery.2,He didn't make his discovery until he experied with untibacterial substances as long as nine years.这两个句子都对吗个?第2个句子主句主语和从句主语相同是否可以写得更简略点,