题目

The time he has devoted in the past 10 years____the disabled is now considered_____ of great value.       A. to helping; being      B. to helping; to be    C. to help; to be          D. helping; being 答案：B列式计算（1）从30里面减去40个0.25的和，再乘0.05，积是多少？（2）用14.81与5.19的和，乘以它们的差，积是多少？（3）0.6 乘0.8的积，加上0.12后，再除1.2，商是多少？