When___more information has been obtained,it will be possible to plan a manned trip to Mars
more information 比较级 不可数
可以用 much ,a little a lot +比较级 再多了解一些信息
When___more information has been obtained,it will be possible to plan a manned trip to Mars
more information 比较级 不可数
可以用 much ,a little a lot +比较级 再多了解一些信息