Complete the sentences with in, at or on and choose the correct alternative. She...

Questão de Inglês da banca IESES aplicada no concurso SCGás (2019). Confira a resolução completa abaixo:

Complete the sentences with in, at or on and choose the correct alternative.

She lives _____ the countryside.
Mark is _____ university.
Don ?t drop litter ____ the ground.
I arrived ____ the USA last week.