They are developing new types of plants that can be grown in poor soil or even sand,and that are

less       to be attacked by pests and diseases.

A.possible

B.probably

C.likely

D.maybe

主片折射率为1.523，曲率半径为0.087，子片折射率为1.654，曲率半径为-0.262，附加光度为（）。

A、+1.00

B、+2.00

C、+3.00

D、+4.00