Why are so many festivals popping up ?

为什么突然冒出这么多音乐节？

More and more firms began popping up to sell the specialized weather derivatives .

突然推出天气衍生产品的公司越来越多。

One thing popping up is called the " internet of things . "

一个突然涌现的事物就是所谓的“物联网”（InternetofThings）。

But certain errors keep popping up .

但是某些错误仍然层出不穷的出现。

Chad said softly popping his knuckles .

乍得轻声说他的指关节弹出。