消防泵扬程不小于选定工作点扬程的（）%。
A、10
B、30
C、65
D、90
参考答案：C
修正概算是在初步设计阶段测算和确定的。 ( )
What he said was _____ difficult for us _____ understand. [ ]
A. so; that
B. very; to
C. too; to
D. very; that
