Exercise

Only when total production expands faster than the rate of labor force growth plus the rate of productivity increase and minus the rate at which average annual hours fall does the unemployment rate fall.

In addition, difficult as it is to believe, there are desert fish which can survive through years of drought in the form of inactive eggs.

In reality, though, the BBC dictionary will be purchased by a far wider range of language learners, as will the other two dictionaries.

要點(diǎn)：這是一個(gè)倒裝句。不倒裝的話，應(yīng)為：the unemployment fall only when ...hours fall. when引導(dǎo)的從句主干為: total production expands faster than the rate ... plus the rate ... and minus the rate...,最后一個(gè)rate又是由at which引導(dǎo)的從句修飾的。
譯文：只有當(dāng)總產(chǎn)量增長(zhǎng)快于勞工數(shù)量加產(chǎn)量的增長(zhǎng)，并減去平均工作小時(shí)時(shí)，失業(yè)率才會(huì)下降。

要點(diǎn)：在由as引導(dǎo)的讓步狀語(yǔ)從句中，句中的形容詞或副詞甚至動(dòng)詞根據(jù)強(qiáng)調(diào)的需要放在句首，而as置于其后。
譯文：此外，讓人難以置信的是，有一種生長(zhǎng)在沙漠地區(qū)的水生動(dòng)物在干旱時(shí)能以其非活性卵的形態(tài)存活多年。

要點(diǎn)：as承接前面從句之語(yǔ)，意為“如。。。一樣”，并且要求主謂倒裝。
譯文：盡管如此，實(shí)際上購(gòu)買英國(guó)BBC廣播公司的字典的語(yǔ)言學(xué)習(xí)者的范圍將會(huì)更大一些，其他兩本字典也是這樣.