[1]

  If you don't have much time, a good and cheap way to shop is in an

   = Unless you                                     동격 ⇒ that you can shop

Internet store. In Internet shopping stores you can order all the things you

                  전치사 + 명사 ⇒ 부사구      S       주문하다,          관계대명사 생략

like just by the click of a mouse. Shopping over the Internet is convenient

                                 동명사구 : 주어     handy, nearby, advantageous

and it can save you time and money. However, there are some problems

                I.O      D.O

with Internet shopping. The main problem is that you don't know for sure

                                                             = certainly

whether or not what you see is what you get. It is because you cannot see

  * what이 이끄는 명사절    S                S.C

* whether or not 이 이끄는 절이 know의 목적어