正常细胞糖酵解途径中，利于丙酮酸生成乳酸的条件是（）
A.缺氧状态
B.酮体产生过多
C.缺少辅酶
D.酶活性降低
E.糖原分解过快
参考答案：A
—What is your friend doing?
—The boy is in the classroom now, doing _______ homework with others. [ ]
A. he
B. him
C. his
D. himself
建筑塑料的特点是( )。
A．耐化学腐蚀性优良
B．比强度低
C．耐磨性差
D．化学稳定性差
