(2)根据课文内容填空(8分)There are two main types of advertisements— c

(2)根据课文内容填空(8分)
There are two main types of advertisements— commercial advertisements and 41 service advertisements (PSAs). A commercial advertisement is one which someone has paid for to 42 a product or service. PSAs are often placed for free, and are 43 to educate people about health., safety, or any other issue which affects public 44 .
This 45 will give you some information about RealCine: how it works, why it is better than 46 cinema,
and how it can be used in other ways. I believe you will be 47 by the RealCine experience, and will agree
that this is an extraordinary 48 that must be developed further.