苯丙酮尿症是由于（ ）代谢途径中（ ）缺陷所导致。
参考答案：苯丙氨酸 苯丙氨酸羟化酶
（），是日本来华的最早的幼教工作者。
Of the making of good books there is no end; neither ________ any end to their influence on man's lives.[ ]
A. there is
B. there are
C. is there
D. are there
