"profit by" 的意思是 得益于；受益；受用。例如：

1. I hope to profit by your advice.

2. We can generate electric power by splitting atoms.

3. Monsanto reaffirms goal to double profit by 2012.

"profit by" 的反义词是 lose by，表示 因…而损失。例如：

1. They lost by a large margin in the election.