Ex1:Put the verbs in brackets into the correct from 1.If we (recycle)___________more,we (help)___________the Earth 2.Factories (not dump)__________waste into rivers if the government (fine)__________them heavily 3.If people (travel)____________to work by bus ,there (be)____________fewer car fumes 4.We (save)_________thousands of trees if we (not waste)_______________paper 5.If we (use)______________water carefully,more people (have)____________ fresh water Cảm ơn mọi người ạ