苯酮酸尿症是由于先天性缺乏
A．苯丙氨酸羟化酶
B．苯丙氨酸转氨酶
C．酪氨酸羟化酶
D．酪氨酸转氨酸
E．酪氨酸酶
参考答案：A
— Did you tidy your room?
— No, I was going to tidy my room but I _____ visitors. [ ]
A. had
B. have
C. have had
D. will have
我国有限责任公司的股东人数限制是（）。
