（）Everyyearmillionsoftrees__

请选择DCBA7a0q4E-t.VEvery year millions of trees ___________to prevent floods, droughts and sandstorms.'@-Q6M/c)P.s'~8})r;O

A. plant'@-Q6M/c)P.s'~8})r;O

B. are planted'@-Q6M/c)P.s'~8})r;O

C. are planting'@-Q6M/c)P.s'~8})r;O

D. were planted'@-Q6M/c)P.s'~8})r;O