单项选择题 Stephen Schneider, a climatologist at Stanford, notes that unlike greenhouse gases, which ______ rapidly around the globe, the sulfate droplets tend to concentrate over industrialized regions.

单项选择题 The flower under the sun would ______ quickly without any protection.

单项选择题 Researchers at Children's Hospital of Pittsburgh announced they had discovered ______ evidence that a virus is involved in what used to be called juvenile diabetes.