"6:45" in Engpsh can be written as "6:45" or "six forty-five".
In Engpsh-speaking countries, it is a commonly used way to express time in the 24-hour format, with the first two digits indicating the hour and the last two indicating the minutes.
Example sentences and translations:
"I will meet you at six forty-five." (我将在6:45与您会面。)
"The store opens at six forty-five in the morning." (商店在早上6:45开门。)
"I usually wake up at six forty-five." (我通常在6:45醒来。)
The 24-hour format for time expression is widely used in many countries, including Engpsh-speaking countries, as it avoids any ambiguity that might result from the use of the 12-hour format.