还是PREP得题

superPPDD

Some patents who do not respond to therapies for depression many simply have received inadequate treatment, having, for example, been prescribed a drug at a dosage too low to be effective or having been taken off a drug too soon.

看到have就紧张

这里为什么要加ing做什么成分呢

顾风

having修饰前面的句子。。。