Have you the people here? It is said that they have a kind of strange illness.
A:hear
B:heard
C:noticed
D:notice
下列说法不正确的是( )
长江中下游地区是长江流域洪涝灾害最集中、最严重、最频繁的地区.与此问题成因无关的是( )
40×2=____
400×2=____
4000×2=____
300×3=____