get a letter from sb.为什么letter不是复数形势,mail letters却是复数?

hear from sb receive（此单词可能有误） a letter from sb get a letter from sb get a letter from sb.为什么letter不是复数形势,mail letters却是复数? receive a letter from sb 是什么意思? l get a letter from my penfriend get a letter from的同义词 get a letter from的同义词 talk about sth.with sb.=receive a letter from 请教hear from sb 和recive a letter from sb的区别和意思. get sth from sb I get a letter from him.He gets a letter --- me是填for还是from get a letter from,received a letter ,heard from his invition的区别求大神帮助 I get a letter from him 同义句转化 get a letter from 等于 _______ ______ 急急 Yes,I _____ just _____ (get) a letter from him. my mother wished (get)a letter from my brother. heard from sb.和 get a better from sb.虽然意思相同, hear from sb 等于 | | | a letter from（3个空） get a ride from sb.还是什么介词