髁状突颈部发生骨折约占下颌骨折的()
A.15%
B.25%
C.35%
D.45%
E.55%
参考答案:B
如果绿色植物被大量砍伐,大气中的二氧化碳就会急剧增加,并能引起温室效应,使地球环境不断恶化。这说明绿色植物能( )
A:调节碳氧平衡 B.过滤空气尘埃
C.降低环境噪声 D.涵养土壤水源
I'm very proud that Beijing is one of ______ cities in the world.[ ]
A. big
B. bigger
C. biggest
D. the biggest