Cheer up!Scientists may well invent ways _____ these problems.

Cheer up!Scientists may well invent ways _____ these problems.  

   A.to solve        B.solving         C.solved      D.solves
   2.There was a basketball match at Jinxing Middle School _____ last Sunday morning.
   A.in                  B.on                C.at              D./
以上两题,请为我解答并写出这样做的原因,希望擅长英语的朋友们帮帮忙,