四倍

Air pollution in the city had reached four times the acceptable levels.

这座城市的空气污染程度曾高达可接受标准的。

Prices quadrupled in ten years.

十年内价格增至原来的。

Each frame is scrubbed four times to erase jaggies, and PGR3 still runs at 60 frames per second - twice the rate of TV.

就是PGR3全屏抗锯齿下画面一流，而且还是以60帧/秒的度运行。

"Some of the well-known types are the durum, emmet , Polish, and poulard. These are tetraploids. and there is the einkorn, which is a diploid. "

有些类型是大家都很熟悉的，比如硬、二、波兰、圆锥。它们都是体。此外还有一，是二体。