If you ' re going to research several technologies and one is an optional requirement of another , research the optional one first as that will boost your research toward the other one unless you have a specific reason for researching the other one 如果可以研究多项科技，而其中一项是另一项的选择性前提，应先研究前提项，这样可以给另一项加速，除非研究有明确的目的性。
