明清以后的书画家常喜欢用吸水性较强的（）纸。
A.生宣
B.熟宣
C.半熟宣
D.冷宣
参考答案：A
Rather than ______ at home, he prefers ______ out to play football even on a cold day.
A．to stay; to go
B．staying; to go
C．stay; to go
D．staying; going
下列哪项是维系蛋白质一级结构的化学键( )
A．糖苷键 B．氢键 C．疏水键 D．磷酸二酯 E．肽键
