"...please try to finish by twenty past seven." "twenty past" assumes a time mentioned in the sentence or the sentence just before. In the sentence above, the speaker wants someone finished in twenty minutes with whatever they were going to do.

1. by twenty minutes later. 2. by twenty minutes past seven. Same meaning.

Where refering to time you need know these words: past = used to say what the time is when it is a particular number of minutes after an hour "twenty past seven" = 7:20 to = used when saying the time, "to" mean before the stated hour "twenty to seven" = 6:40 quarter = 15 minutes "quarter to seven" = 6:45 "quarter past seven" = 7:15 half past = a particular hour is 30 minutes later than that hour "half past seven" = 7:30

By twenty past seven (7.20).

= twenty past seven