1.It is amazing that the little boy can swim across the river _____100 meters wide为什么用measuring而不用measured
2.when the newspaper boy got to a blue door ,_______,which frightened him away as fast as possible为什么用out rushed a fierce dog 而不用rushed out a fierce dog
3.i ____that all windows are shut.i did it为什么用am sure 而不用am clear 或make sure 或make clear