Inversion of passive voice (i think so)

Could someone please tell me how to complete the second sentence so that it has a same meaning to the first one using the given word? You must use between three and six words including the word given.

1. Your mobile phone should be switched off at all times during the performance.

world: should
2. Under no …. your mobile phone switched on during the performance.

Please note that you may not modify any part of the sentence apart from ‘…’. So ‘Under no circumstances should your mobile phone be switched on during the performance’ is incorrect.

I tried with: "circumstances should be" – but I think this is incorrect
I don’t have any other idea. Please help.