Sam some knowledge of the computer just by watching others working on it.
The hunter shot at the birds ______ the big tree, only to shoot ______.
—How long did David work here? —For half a year, he didn't leave much_______on us.
_____ in a poor family made Tom very dilligent when he was still young.
As many successful businessmen believe, courage is as ______ to pioneering work as the intelligence, even more so.
— May I ask for three days off tomorrow? —______. You know, the May Day holiday is just around the corner and every salesgirl is as busy as a bee.