De estos textos, que oraciones están en voz pasiva?

De estos textos, que oraciones están en voz pasiva? A customer wants to know how a machine works Excuse me. How does this device work? Salesperson : It's an electronic translator. You speak into this built - in microphone, and it translates your words into ten languages. How do I choose the language? Just press this button, and. Wow! The Multilingua is very useful, especeally for business people ande travelers. What's this for? That's the volume control. You put it on high to make the sound softer, of couse. And what's the price? Well, it's on sale. Only What is it made of? Gold? A woman lost her umbrella She wants to know if someone found it Could you help me, please? I left my umbrella on the train yesterday. Maybe it was found and brought here. We have many trains, Ma'am Do you remember which one? Yes, it was the three o' clock train from Nothbrook Would you describe your umbrella? Certainly. It's a red a pink Chinese umbrella. It's made of silk and bamboo, and it has a wooden handle Let me have a look. Is this the one? Yes, thank you. You've been very helpful.