Working the land
用他的雜交水稻種子，農民們種出的糧食比以前多了一倍。
倍數表達法：
a＋be＋倍數＋as＋adj.＋as＋b
a＋be＋倍數＋比較級＋than＋b
a＋be＋倍數＋（由某些形容詞變化而來的）n.＋of＋b
i’m not going out with a man who’s twice as old as me.
我不愿意和一個年紀比我大一倍的男人一起參加社交活動。
we got three times as many people as expected.
來的人超過我們預料人數的兩倍。
you’re not half as clever as you think you are.
你可不像自己想像的一半那么聰明。
高手過招
單項填空
what a table! i’ve never seen such a thing before. it is it is long. （ 原創）
a. half not as wide as b. wide not as half as
c. not half as wide as d. as wide as not half
解析：選c。考查倍數表達法。表達倍數的結構應該是：a+ be+倍數+as+ adj.+ as +b。as... as中間是形容詞或副詞的原級，而不可以是比較級或最高級。
15. this also keeps the air, soil, water and crops free from chemicals.
這還可以讓空氣、土壤、水以及農作物不受化學物質的污染。
keep ...free from 無……的；免于……；擺脫……（常用作表語、后置定語或補語）
聯想拓展
be free to do sth. 自由地做，隨意地做
set sb. free 釋放某人
get/give sth. for free免費得到/贈送
a smokeˉfree room/area無煙室/區
free of charge免費
高手過招
完成句子
用這個東西把桌子罩住，免得有灰塵落在上面。
the table dirty by putting a cover over it.
答案:keep; free from