用英语怎么说7 40

"7:40" can be translated into English as "seven forty." This way of expressing the time is based on the way that hours and minutes are typically written and spoken in English.
Here are some examples of sentences that use "seven forty" to express the time:
"I have to be at work at seven forty." (我必须在7:40到达工作地点。)
"The train leaves at seven forty." (火车在7:40发车。)
"We're having a meeting at seven forty in the conference room." (我们将在会议室7:40开会。)