多项选择题 （）是制约物联网产业发展的关键要素。

多项选择题 物联网时代将带来的改变有（）。

单项选择题 听力原文：M: When will the English evening be taking place?W: It's at 7:00 on Friday evening.M: Where will the English evening be held?W: In the department hallM: Who will attend the party?W: All the students of our department.M :There are 15, and well invite the audience to add to the program.M: What's on?W: Singing, dancing, poetry reading, short plays, and so on.M: Are they going to be interesting?W: Well, you'll know after you've seen them.Q8. When will the English evening begin?(14)A．At 17:00 on Friday evening.B．At 7:00 on Friday evening.C．At 6:30 on Friday evening.D．At 7:00 in Friday morning.