They all doubled up when I told my joke.

当我讲笑话时, 他们都笑得直不起身子来。

Because of the housing shortage, many couples had to double up in one tiny apartment.

由紧张, 许多对夫只好挤在一栋。

The sad news doubled him up.

噩耗使他悲痛欲绝。

The carpet won't double up.

这地毯不能折起来。