The village no longer existedbecause it had been submerged, and all the valley too. The lake was not a naturalone, but a man-made reservoir.

　　31.The village no longer existed because it had been submerged, and all the valleytoo.

　　村庄已不复存在，因为已经为水所淹，山谷也被水淹没了。

　　语言点:句子结构分析:Because引导原因状语从句，一般不与so在同一个句子里出现。

　　32.The lake was not a natural one, but a man-made reservoir.

　　这不是一个天然湖泊，是一座人工修建的水库。

　　语言点:句子结构分析:Not…but…可理解为“不是…而是…”。