Vitamin D helps our bodies make a special chemical,and this special chemical, , affects o

Vitamin D helps our bodies make a special chemical,and this special chemical, ,
affects our brains,making us feel happy.
A. in turn
B. in particular
C. in advance
D. in short

A. in turnB. in particularC. in advanceD. in short解析： 考查介词短语在语境中的用法。in turn反之，反过来；in particular特别，尤其；in advance提前，预先；in short简而言之。句意为：维生素D帮助我们的身体产生一种特殊的化学物质，而这种化学物质反过来又影响我们的大脑，让我们感到高兴。根据题意可知，A项正确。

就是这个解释