With age, the mineral content of human bones decreases, ______them more fragile.
A．make
B．and to make
C．thereby making
D．which it makes
儿童多动症属于
A.学业相关问题
B.情绪问题
C.品行问题
D.顽固性不良习惯
E.广泛性发育障碍
为了探讨FLX和OFX两种药物对泌尿系感染的疗效，研究者选择了120例该病患者，随机分为服用A药组和服用B药组，采用盲法观察疗效，以确定两种药物哪个疗效更好。这种研究方法是
A、比较试验
B、观察试验
C、临床试验
D、预防试验
E、干预试验
任何一个儿童的动作发展总是沿着抬头一翻身一坐一爬一站一行走的方向进行。()
Which of the following italicized phrases is INCORRECT？
A．I can carry as much paper as you can.
B．He is as busy as a bee.
C．She is as a good teacher as your father.
D．He was as experienced as his brother was green.