8点15分用英语两种表达是：a quarter past eigh、fifteen past eight；

quarter：n. 四等份之一; (正点之前或之后的)15分钟，一刻钟; 三个月时间; 季度; 季。

past：adj. 过去的; 昔日的; 刚过去的; 刚结束的; 从前的; 以往的。

A quarter of the residents are over 55 years old

1/4的居民年龄在55岁以上。

Still to come, the financial news and the weather at a quarter to two.

稍后是1点45分的财经新闻和天气预报。

A quarter of the working class voted for him.

工薪阶层中有1/4的人投票支持他。

promptly at a quarter past seven, we left the hotel.

我们于7点一刻准时离开了宾馆。

Farmers could see a quarter of their income swallowed up by the interest rate rise.

农场主会发现由于利率的上涨，收入减少了1/4。