Are the following questions ok?
how could somebody go to school with another person constantly but barely know that person?
don’t you think that anybody who has the true intention to practice would have made sure that they can get into the theater?

Question

Answer

‘Constantly’ doesn’t have a clear meaning here. You have to be more specific. ‘/For many years/day in and day out/everyday/‘
Etc.

In the second, ‘they’ is fine, but far more natural would be ‘truly intends’ instead of ‘has the true intention’.

Evden çıkmadan dil öğrenme fırsatını kaçırmayın. Deneyimli dil eğitmenlerimizden oluşan seçkimize göz atın ve ilk dersinize şimdi kaydolun!