题干
---- Look! So many colourful kites________ here.
---- You don’t know? It’s said kites _______ well in this area.
---- You don’t know? It’s said kites _______ well in this area.
A：are sold; are sold
B：are selling; sell
C：are selling; are sold
D：are being sold; sell
答案(点此获取答案解析）
D
等症状。这一事实说明铁的作用为( )