We’ve just heard a warning on the radio a typhoon may be on its way．
A. what
B. when
C. which
D. that
网友回答
A. what
B. when
C. which
(答案→)D. that
解析：考查同位语从句。That引导同位语从句that a typhoon may be on its way解释名词warning的内容；that在句中不充当任何成分，没有任何意义，只起连接和引导作用。故D正确。