改进冀Ⅱ优型节能日光温室:跨度8.0m,脊高3.65m,后墙高度2.5m,后坡水平投影长度1.5m,墙体内外侧为砖墙24cm,内填12cm厚的珍珠岩。()
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【C10】
A. poorest
B. richest
C. common
D. best
园艺设施在寒冷季节透光率只有自然光的50~70%,透明覆盖材料用时间长而染尘、老化等因素,使透光率甚至降的更低。()
聚乙烯透过太阳辐射能力优于聚氯乙烯,但,聚乙烯保温性能较差,棚内日温差大。()
Many ways have been found______small and simple machine to process large and complicated machine parts.
A. by using
B. to use
C. using
D. used