are 后面接动词ing形式表示现在进行时，比如they are studying，他们正在学习。
例句
They are skilled debaters.
他们是娴熟的辩论家。
Materially they are no better off.
他们的物质生活并没有改善。
They are not eligible for sick pay.
他们没有资格领病假工资。
They are sold in many different colours.
这些有多种颜色供选购。
Now they are producing throwaway razors.
他们正在生产一次性剃须刀。
