1 Complete the zero conditional sentences. Use the correct form of the verbs in brackets. 1 If you __________ (recycle) your clothes, it __________ (help) the environment. 2 If someone __________ (leave) a light on, I always __________ (turn) it off. 3 If my sister __________ (watch) a sad film, she __________ (cry). 4 When my parents __________ (not be) at home, we __________ (cook) dinner. 5 When public transport __________ (be) reliable, people __________ (not need) to use their cars.