请你根据广告的优缺点填写一个适当的词，使短文完整。

     In the modern world, advertising is  _ 1    ! Some people like ads but others hate ads.

     I think it often offers some advantages and disadvantages.

     Some ads are very useful. They can tell people how to compare two different products so     2_   

people can buy the better one. They can also help you     3     money.

     However there are also some disadvantages. Some ads can be confusing or misleading. Sometimes

the words sound good but don't tell anything real.  So you have to be     4     not to be cheated (欺骗).

We shouldn't believe     5     .

对阈值的下列叙述，错误的是

A．是指能引起组织发生兴奋的最小刺激强度
B．是指能引起组织产生动作电位的最小刺激强度
C．阀值即阈电位
D．是判断组织兴奋性高低的常用指标
E．组织的兴奋性与阈值成反比关系