简答题What has the Dutch designer designed? A、A large tower that can purify air. B、A magic pocket that can create clean air. C、A most livable city that is smog-free. D、A device to measure the pollution level.简答题What do we learn about Smog Free Tower? A、It has been widely used in hospitals. B、It can be very profitable in the future. C、It can make surrounding areas completely clean. D、It has been under development for three years.