一般来说材料的孔隙率越大,其导热系数越小,但如果是粗大或连通的孔隙,尽管孔隙率大,其导热系数反而增大。
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在满足使用要求的前提下,应尽量使用较大牌号的石油沥青,以保证较长使用年限。
A. 对
B. 错
-Mother, could you pass me some ( )? It’s so delicious. -OK, but only a little.
A. butter
B. roses
C. bananas
D. sandwiches
-What’s in the cabinet? -A few ______, but little _____.()
A. strawberries; coffee
B. coffee; strawberries
C. strawberry; coffees
D. coffees; strawberries
He gave us ( )on how to give up smocking.
A. some advices
B. some advice
C. an advice
D. a advice
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