病毒的包膜成分包括（）
A.酶类、脂质、核酸
B.核酸、酶类、糖类
C.糖类、脂质、核酸
D.脂质、蛋白质、糖类
E.糖类、脂质、核酸
参考答案：D
I would have finished my paper if it was at all possible, but I was fully occupied the whole of last week.
A．had it been
B．were it
C．it had been
D．it were
根据《建筑基坑支护技术规程》4.3.8要求，排桩桩间土防护采用喷射混凝土面层时，面层内配钢筋网的纵横间距不宜大于（）mm。
A.100
B.150
C.200
D.250
