Flying kites, some researchers point out, can not only bring about joy to us, but also promote our physical and mental health.
A. which
B. what
C. as
D. where
网友回答
A. which
B. what
(答案→)C. as
D. where
解析：句意：正如一些研究人员指出的，放风筝不仅能给我们带来快乐，而且也能促进我们的身心健康。这里使用的是as引导的非限制性定语从句， as指代主句的内容，而且在定语从句中as做宾语，which引导非限制性定语从句只能放在句末，what不能引导定语从句，where在定语从句中不能做宾语，所以选C。