Translation of "Roller" in Chinese

I got the roller skates for nothing.

我免費得到溜冰鞋。

Can we roller-skate in this park?

我們可以在這個公園裡玩四輪溜冰嗎?

The shop's roller door is already shut.

商店的卷簾門已經關上了。

I can't keep this up. It's an emotional roller coaster around here and all we have to do is look at the boss's face to know whether everybody is going to be happy or sad.

我們上班時的情緒，就像坐過山車一樣 ﹣ 老闆臉上一現出不悅的神色，我們就要吃苦頭；老闆臉上有了笑容，我們才能鬆一口氣。這樣的工作，我不想再幹下去了。