WeChat（微信）is one of the most convenient ways of ．（　　）

I found in the room．Where have they gone？

They've gone to Dave's birthday party．（　　）

His grandfather did his best to keep the tree ，but it died in the end．（　　）

The cover of the book comfortable．It's made of silk．（　　）

Humans can not make progress dreams．（　　）