一般规则是字母i在e前面，但在c之后除外：
believe sieve
但是：
deceive receipt
下面这些词例外，都拼写为ei：
beige feint heir reign their
counterfeit foreign inveigh rein veil
deign forfeit inveigle seize vein
eiderdown freight leisure skein weigh
eight heifer neigh sleigh weight
either height neighbour sleight weir
feign heinous neither surfeit weird
