New ways _____ to prevent the river _____.

A．have found out, from polluting

B．have found, from being polluted

C．have been found out, from being polluted

D．have been found, from being polluted

上颌第一磨牙远中接触区位于（）。

A．1/3处

B．1/3水平的颊1/3与中1/3交界处

C．自1/3水平的中1/3处

D．中1/3处

E．1/3水平的中1/3与舌1/3交界处