previous best
以前最好
例句:
1.
Nasa radar astronomers picked up its track on friday and were immediately able to narrow its position to within one kilometer--50 times better than their previous best estimate.
nasa的雷达天文学家周五发现了它的轨迹，并立即将它的位置精确至一公里以内的区域，比此前最好的估计精确了50倍。
