They generally take two years time, in this period of time, Their contribution is likely to be less than with the training they have to spend the same proportion of the cost.

他们一般需要两年的时间，在这一段时间里，他们的贡献可能达不到与培训他们所花费的成本的同等比例。

youdao

Mr Obama's failure to take on the spend-alls in his own party will cost him politically.

ECONOMIST: The Obama presidency, one year on