have been to do是什么用法

The object of the HIPEROAD project has been to make the optimisation loop automatic in large part in order to greatly reduce the time needed to evaluate and improve the sketch design provided by the stylists.
请教翻译
主要问题是HAS BEEN TO DO不知道怎么理解。。。都没见过这种用法。。。

第1个回答  2010-04-18
过去分式