с решением по англ! Are these sentences right or wrong?
1. An operator can know how to use the telephone system. An operator may know how to use the telephone system. An operator should know how to use the telephone system.
2. I suggest we should buy a mobile telephone to stay in touch. I suggest we bought a mobile telephone to stay in touch. I suggest to buy a mobile telephone to stay in touch.
3. If Tom called leave me a message. Should Tom called leave me a message. Must Tom called leave me a message.
4. You should deal with the calls promptly in the morning but I see that they are not answered. You should have dealt with the calls promptly in the morning but I see that they are not answered. You should be dealing with the calls promptly in the morning but I see that they are not answered.

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