软件开发环境是全面支持软件开发全过程的（）集合。
参考答案：软件工具
根据所掌握的知识并结合近年来学术研究动态，试论述国民党败退大陆的原因。
As there was a power failure in the hospital, the doctor had to （）operation.
A.call for
B.call off
C.call on
D.cal lout
