Don't forget the appointment with the principal at the registry office, _____you

It is impossible that you achieve your goal without effort,         ?

----____ have you lived here?----Since last year.

Many of your classmates dislike having to stay up late doing their lessons, _____? 

Since it will take years to know the effect of genetically modified food, it’s more sensible to give it a second thought before we eat it,        it?