in advance 和ahead区别
问题描述：
in advance 和ahead区别
答
in advance 是发生在某事之前，提前，预先的意思
eg .Book tickets 10 days in advance．
ahead 也有提前，事先，预先的意思，相当于 in advance 用法如下：
I cook rice two or three hours ahead．
I think we can finish the work ahead of time．
答
in advance 正在前进中
例:The army is in advance.军队工向前推进.
而ahead 则是:在前面 或是 领先.
例:Traffic ahead is very heavy.前面的交通很挤逼
He is ahead of the others.他正领先了其它各人.