完成句子（共3小题；每小题1 分， 满分3分）
1. 他的朋友患有头痛好多年了。
His friend has been_________ _________ headaches for some years.
2 我们必须利用每一分钟去学习
We must ______ ________ ________ every minute to study.
3 他因为腿不方便而行走缓慢。
He walked slowly_______ _______ his bad leg.