If, in conditions of tolerable average employment, this net yield turns out to be infinitesimal, time-honoured methods may prove unavailing.

如果在可容忍的平均就业条件下，这种净收益变得无穷小，那么历史悠久的方法可能会被证明是无用的。

The high rates of interest from mortgages on land, often exceeding the probable net yield from cultivating the land, have been a familiar feature of many agricultural economies.

土地抵押贷款的高利率， 往往超过耕种土地可能产生的净收益， 这已成为许多农业经济体的一个常见特征。

Provided there was some measurable unwillingness to undertake risk, there would also be a positive net yield from the aggregate of such assets over a period of time.

如果存在某种可衡量的不愿承担风险的意愿，那么在一段时间内，此类资产的总和也会产生正的净收益。

But it is not unlikely that, in such circumstances, the eagerness to obtain a yield from doubtful investments might be such that they would show in the aggregate a negative net yield.

但在这种情况下，从可疑投资中获得收益的渴望可能会导致总体净收益为负，这并非不可能。