英语,1.We must plant more trees____Aand protected our city B.t

英语,
1.We must plant more trees____
Aand protected our city B.to stop the sand
C.to protect the sand D.to saved the sand
2.They waited silently____
A.for the film begin B.when the film begin
C.to the film begin D.for the film to begin
3.This piece of bread is____hard____.
A.very,to eat B.so,to eat
C.too,to eat D.enough ,for eat