典型苯丙酮尿症的病因是由于患儿肝细胞缺乏（）。

A.葡萄糖-6-磷酸酶

B.苯丙氨酸氢化酶

C.四氧生物喋呤

D.淀粉酶

E.机制尚不明确

---Tom’s been sent to the USA for further study. What about his twin sister?

--- _____.How lucky they are!

A．So has she

B．She is too

C．So is she

D．So she has