A GAS OR OTHER SUBSTANCE WHICH IS SENT OUT INTO THE AIR IS _______

33. - File thứ 5: de_va_dap_an_45_phut_so_3_lop_11_sach_moi_311201817
File thứ 5: de_va_dap_an_45_phut_so_3_lop_11_sach_moi_311201817

33. A gas or other substance which is sent out into the air is _______.

A. emission B. carbon footprint C. disease D. greenhouse gas