对啊!以前老师说的,是 have a meal,或者 have breakfast/lunch/dinner 。。。但原来不是这样的。看看 Longman Dictionary:
COLLOCATIONS

eat (your) lunch
have (your) lunch (=eat lunch)...
连 Oxford Dictionary 解释 lunch 作动词用的时候也是:
verb [no object, with adverbial]
eat lunch: he told his wife he was lunching with a client