WE NEED TO MAKE SURE THAT OUR WASTE WILL BE _____ AND WILL NOT POLL...

7. - DE THI THU DAI HOC MON ANH VA DAP AN
DE THI THU DAI HOC MON ANH VA DAP AN
7. We need to make sure that our waste will be _____ and will not pollute the environment. A. harmful B. harmed C. harm D. harmless