Conditionals in English
Conditionals, also known as ‘if clauses’, describe a certain condition and its result. There are four types of conditionals in the English language: first conditional, second conditional, third conditional and zero conditional. We can also mix second and third conditional.
Prepositions of Time - IN, ON, AT
We use IN for centuries, decades, years, seasons, and months: Peru was colonized in the 16th century.
We use ON for specific days and dates: They’re arriving on Wednesday.