He passed the letters to the Department of Trade and Industry.他把信交给了贸工部。I am expecting several important letters but nothing has arrived.我正在等几封重要的信件，可是一封都没到。We delved through a sackful of letters to draw the winning name...
In Morse code all letters are four or fewer characters long.在Morse电码中所有字母的长度只有四个或不到四个符号.He covered his tracks, burnt letters and diaries...他掩盖形迹，烧毁了信件与日记。They used chisels to chip the letters into the stone.他们用凿子在石头上刻出字母...
蚯蚓吃下大量土壤，排出肥力丰富、物理结构理想的腐殖质。Earthworms consume large amounts of soil, and produce a rich humus, perfect in texture.有机物分解的最后程序称为腐殖质化.The final process in organic matter decomposition is known as humification.腐殖质是已知能够覆盖滤膜的物...