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.