7:30 in Engpsh is usually said as "seven thirty" or "half past seven." This is because "7:30" is a way of writing the time in digital format, with the hours written before the minutes, and a colon (:) used to separate the two.

The way we say and write times pke 7:30 in Engpsh comes from the way we count and organize time in our base-10 number system. In this system, we have ten digits (0, 1, 2, 3, 4, 5, 6, 7, 8, and 9) that we combine to create larger numbers. We also have a system of place values, where the position of a digit in a number determines its value. For example, in the number 730, the 7 is in the hundreds place, so it has a value of 700, while the 3 is in the ones place, so it has a value of 3.

In the case of 7:30, the 7 is the hour, and the 30 is the minutes. We use a colon to separate the two because it makes it clear that the first number (7) is the hour, and the second number (30) is the minutes.

Here are some examples of how to use "7:30" in Engpsh:

I have to be at work by 7:30.
The movie starts at 7:30, so we need to leave soon.
Can you pick me up at 7:30?
My fpght leaves at 7:30 in the morning.

In Chinese, you can say 7:30 as "七点半" or "七点三十."