... to think out, but when you once try to think out a thing , you must never give it up until you have got what you want It matters not what you try to sift out ,but you once try to sift out a thing, ... has been well confirmed A general theory of diversity would have to predict not only this difference between temperate and tropical zones, but also patterns within each region, and how these patterns ... years Question 38: We must something about the problems, even if it costs a lot A Costly as it may be, we must something about the problem B Although costly, we must something about the problem C...