第17题: [单项选择]丙酮酸脱氢酶系受到哪些因素调控:() A. 产物抑制、能荷调控、磷酸化共价调节 B. 产物抑制、能荷调控、酶的诱导 C. 产物抑制、能荷调控 D. 能荷调控、磷酸化共价调节、酶的诱导 参考答案:A
第18题: [单项选择]______ in debt to anyone, Tony is very careful about the loans. A. Never has been B. Having never been C. Never being D. Never having been 参考答案:D 答案解析:[题解] 非谓语动词的否定形式,否定词放在句首。选项A,看上去好像是倒装句式,但是没有与其颠倒的主语。副词never一般与完成式连用。本句的意思,也表明他从来没有欠过债。