Choose the appropriate modal verbs to complete the sentences. 1. sir, don't you know that when flying you (have to/must) show you passport. 2. i(have to/must) be at the meeting at 6 p. m. so i can't join you for dinner. 3.there are many guests in the house, george will (have to/must) sleep on the sofa 4. people (have to/must) realize there are limits to what we can do.