There are laws in some countries which forbid advertisements _______ at inappropriate times and places.[ ]

A．being shown  

B．shown

C．show  

D．to have shown

确定胎儿安危最简便而准确的方法是

A．催产素激惹试验

B．胎动计数

C．尿雌三醇测定

D．胎儿电子监护

E．羊膜镜检查