I had flu for a couple of days.
1、我感冒了一两天。
have flu 患流感，也可以说成: have the flu, catch a cold, have a cold
a couple of days （虚指）一两天
2、发音技巧
for a couple of days 需要连读/fɔ:rə/ / kʌpləv/
3、使用语境
Interpreter: I hear you've been ill.
翻译：我听说你病了。
Athlete: Well, I had flu for a couple of days, but I'm fine now.
运动员：嗯，我感冒了一两天，不过现在好了。
这里要特别注意的是well的用法。
well：
used to pause or give yourself time to think before saying something
嗯，这个〔用于停顿片刻或使自己在说话前有时间考虑〕