Two prepositions we use to talk about times are by and until.
Today, we'll look at how we can use by and until in our conversations.
By (+ time) means the same as "not later than." It is used to show that something happened or will happen before a time. For example:
◆I got to the station by 2.
◆My company is going to open a new office by the end of the year.
◆I usually wake up by 6:30 in the morning.
You can usually replace by with before and the meaning will be about the same.
◆I got to the station before 2.
◆My company is going to open a new office before the end of the year.
◆I usually wake up before 6:30 in the morning.
However, sometimes the meaning will be a little different.
◆My boss wants me to finish the report by Friday. (It is still OK to finish on Friday.)
◆My boss wants me to finish the report before Friday. (It is not OK to finish on Friday.)