α废物主要产生于（）。

单项选择题What makes the childrens common vaccines less effective according to the new study？（）

A．The exposure of chemicals they used in childhood.
B．The reduction of a series of chemicals in childhood.
C．Childhood consumption of chemical products.
D．Childhood contact with chemical products.

单项选择题The 34-year-old British woman is extremely afraid of metal forks because（）.

A．she is afraid that they may hurt her
B．she couldn’t bear their sound on plate
C．she has been injured by them before
D．she has never used them before

单项选择题几项调控房价的措施相继出台，说明政府_____房价增长过快的态度相当坚定。填入划横线部分，最恰当的一项是（）。

A．控制
B．抑制
C．压制
D．管制

单项选择题不属于制约因素范围的是( )。

多项选择题一切电话中断：指行车室内列车调度电话、站间行车电话、自动电话、（）在内的电话均无法联系。

A.列车无线调度通信设备
B.FAS台
C.地方移动电话
D.GSM-R手持台