Open the brackets and fill in the gaps. Mind the positive or the negative forms of the imperative sentences. 1) (To switch off) ______________________________ your mobiles. 2) (To read) _____________________________________ the instructions. 3) (Not to feed) _____________________________________ the animals in the zoo. 4) (To clean) _________________________________ your teeth. 5) (Not to swim) _______________________________________ in this lake. 6) (Not to talk) _______________________________________ to strangers.