Косвенная речь"Nobody will know." I thought nobody​

NO PROBLEM WITH THE NEW FIRMWARE

1)  Do our students go to exhibitions regularly?
our students go to exhibitions regularly,don't they?
Where do our students regularly go?
who goes to exhibitions regularly?
Do our students or teachers go to exhibitions regularly?
2) were their children playing computer games yesterday from 5 till 6 pm ?
Their children were playing computer games yesterday from 5 till 6 pm,weren't they?
Who was playing computer games yesterday from 5 till 6 pm?
Were their children playing computer games or listening to music yesterday from 5 till 6 pm?
When were their children playing computer games?

Доктор медицины Евгений Суслов научился диагностировать рак у пациента по слюне. Этот эффективный, безопасный и безболезненный. Результат можно узнать через несколько часов. Этот новый метод диагностики является одним из 10 лучших изобретений Украины.  Этот дешевый может миллионы жизней.

Doctor of medicine Eugene Suslov learned to diagnose cancer in patient's saliva. This method is effective, safe and painless. The result can be found in a few hours. This new method of diagnosis is one of the top 10 inventions of Ukraine. This cheap method can save millions of lives.