Period 1AListen and number1The black smoke from the factories makes the air dirty.2Look at the smoke from the cars.3We should put rubbish in the bin.4The rubbish makes the river dirty.5Trees can help keep the air clean.(a 4b 2c 1d 3e 5)BRe

Period 1AListen and number1The black smoke from the factories makes the air dirty.2Look at the smoke from the cars.3We should put rubbish in the bin.4The rubbish makes the river dirty.5Trees can help keep the air clean.(a 4b 2c 1d 3e 5)BRe