促进药物生物转化的主要酶系统是（）
A.单胺氧化酶
B.细胞色素P-450酶系统
C.辅酶Ⅱ
D.葡萄糖醛酸转移酶
E.水解酶
参考答案：B
一块平行四边形的木板，底为5米，高为3米．以每平方米28元计价，它的价格是多少？
If you ________ home without a word, your parents wouldn't be so worried now.
A．didn't leave
B．couldn't have left
C．hadn't left
D．shouldn't leave
