高考时间用英语表达通常有以下几种方式：
日期表达
在每年的6月7日和6月8日进行，因此可以说 "The college entrance examination is held on June 7th and 8th every year."
时间表达
考试时间为上午9点开始，可以表达为 "The exam starts at 9:00 a.m."
复合表达
如果需要同时表达日期和时间，可以这样写："The college entrance examination is scheduled for June 7th and 8th, 2023, starting at 9:00 a.m."
结合以上信息，高考时间用英语表达可以是：
"The college entrance examination is held on June 7th and 8th every year."
"The exam starts at 9:00 a.m."
"The college entrance examination is scheduled for June 7th and 8th, 2023, starting at 9:00 a.m."