He has flu.和He has a toothache.这两句话一个他得了流感,一个是他牙痛.为什么flu不要用a

He has flu.和He has a toothache.这两句话一个他得了流感,一个是他牙痛.为什么flu不要用a He has a stomach ache 和 He has flu 为什么一个有A一个没有A he has flu说成he has a flu行吗? 英语翻译他得了流感,He _____ _____ flu,_________ ____?= He ______ flu, He has a flu .哪里错了? 得了流感是have the flu 还是have a flu 患流感英语是have flu还是have the flu还是have a flu dave has a flu .so he must stay in bed .改错 问一下英语爱好者rarry has the flu.His nose is running.He coughs a lo She has flu.为何不用加a mr.wang has stay in_bed because he has _ flu. He has a toothache.改为否定句.