Are the following sentences grammatically correct? Check them, please:
1 - The shops have been open since 8 o'clock in the morning. / The shops are open from 9 a.m. to 1 p.m. on Saturday.
2 - The shops have been opened by us. / The shops are opened every morning by their managers.
Could you explain your choices, please?
They're fine grammatically, but The shops have been opened by us- is not a very natural sentence. In most contexts, we'd use the active and say we opened the shops.