The report says the bugs invaded after farmers decreased their use of insecticides by planting Bt cotton.

VOA: special.2010.05.25

So let me go back now to this expression, x=at^/2+c+bt.

让我们再回到这个式子,x=at^/2+c+bt

耶鲁公开课 - 基础物理课程节选

In that case, y will be -gt^/2+c+bt.

在这个情况下y=-gt^/2+c+bt

耶鲁公开课 - 基础物理课程节选

The scientists say their research shows that the Bt cotton has become a source of mirids.

VOA: special.2010.05.25

Much of the cotton grown in northern China is a Bt variety made by Monsanto.

VOA: special.2010.05.25

Bt is used as a pesticide to fight cotton bollworms, corn borers and other pests.

VOA: special.2009.10.27

Around the world, farmers grow an estimated sixteen million hectares of Bt cotton.

VOA: special.2010.05.25

It also involved Bt cotton, a plant genetically engineered to resist that threat.

VOA: special.2010.05.25

Another example of scientific progress involves a natural bacterium known as Bt.

VOA: special.2009.10.27

Bt is a bacterium that was discovered in the early twentieth century.

VOA: special.2010.05.25

Then scientists learned how to put a Bt gene into cotton plants.

VOA: special.2010.05.25

Bt cotton plants naturally kill bollworms.

VOA: special.2010.05.25

Different companies produce Bt cotton.

VOA: special.2010.05.25