_______should not be allowed to get ears pierced.

There is a(n) _______ bus service into the center of town, which makes it much easier for farmers to go to sell their vegetables there.

These experiences ______ me _____ the drug’s harmful effects. 

Einstein’s Theory of Relativity is so ________that most of us can not understand it.

It sounds like a good plan, but there are some _____ difficulties in carrying it out.