Betty：Hi, Mum!

Mum：Hello, Betty! Where are you now?

Betty: I'm____ (stand) on the Great Wall of China and____ (talk) to you. Mum：Really? That's great.

Betty：We're on a school trip.

Mum: What about the____(other)? Are they with you?

Betty: Well, right now Tony is ____(eat) a delicious ice cream. Wang Hui is ____take) lots of photos. Daming ____(have) lunch in the sun. And just now Lingling _____(buy) a few presents and postcards. Because they ____(be) on sale in the shop.

Mum: I'd like a postcard too, and please take some photos of the Great Wall and send____(they) to me by email.

Betty: OK. We're enjoying the school trip a lot. Anyway, it's time____(go) back to school now. Bye, Mum!

Mum：Bye, Betty!

物态变化与我们的生活密切相关，下列关于物态变化的说法，正确的是（　　）

下列叙述不正确的是（　　）