1、the black economy pays no taxes.
黑色經濟不支付稅款。

2、No one knows how large the black economy really is.
沒有人知道黑色經濟到底大到什么程度。

3、Dealing with the black economy in this broader sense, one must also consider tax evasion.
關于廣義的 * 經濟，必須也考慮到稅款的偷漏。