UP TO NOW, WE _______ THE POLLUTION PROBLEMS YET. A. HAVEN’T SOLVE...

37. - DE KIEM TRA ANH VAN SO 1HOT
DE KIEM TRA ANH VAN SO 1HOT

37. Up to now, we _______ the pollution problems yet.

a. haven’t solved b. are not solving

c. hadn’t solved d. will not have solved