during 和in的区分

1. during + some time只表示“在...期间”；
而in + some time有两个含义：“在...之后”和“在...期间”.
如：I'll return in 20 minutes. 我会在20分钟后回来.
2. 如果两者都表示“在...期间”时,有时可以换用.区别如下：
1）如果其后的宾语是明显表示时间段的短语,如twenty minutes, half an hour, two years等时,一般只用in.
2) 如果其后宾语是表示能延续一段时间的表示事情/活动类的名词时,则一般只用during.
如：during the summer/winter holiday；during the vacation；during my visit to Beijing；during his stay in Shanghai.