Paul is good, hard-working and intelligent;           ，I can't speak too highly of him.    [ ]

A. as a result                  

B. in a word    

C. by the way                

D.on the contrary

下列关于白肋烟叶片结构与质量关系描述正确的是（）

A.中下部烟叶叶片结构松的烟叶质量尚好

B.上部稍密的烟叶有不同的杂色

C.中下部稍疏松与疏松的烟叶质量较高

D.密和松的烟叶质量较好