USAGE NOTE 用法说明: during and 和 for
During answers the question 'when'. 回答 when（何时）一类的问题时可用 during:
She learned Italian during her stay in Milan. 她在米兰逗留期间学会了意大利语。
For answers the question 'how long?' 被问道 how long（多久）时，可用 for 作答:
He studied in the US for five years. 他在美国读了五年书。