七点用英文怎么说两种形式

"7 o'clock" 可以说作 "seven o'clock" 或 "seven in the morning/evening".

"O'clock" 来源于 "of the clock", 是一种口语化的说法.

例句:

It's seven o'clock. (现在是七点钟)
The movie starts at seven in the evening. (电影在晚上七点开始)