We stopped in the afternoons to fish for a few minutes in little rivers turned black by the acid of cypress trees.

VOA: special.2010.01.30

When you think about a gene or a transcript, the messenger RNA copy of a gene, you know that for every sequence of a nucleic acid there's a complimentary sequence.

当你们考虑一段基因或者一个,转录一段基因的mRNA拷贝,你们知道每个核酸序列,都有互补序列

耶鲁公开课 - 生物医学工程探索课程节选

Soil should also be tested for its pH level, a measure of the acid and alkaline balance.

VOA: special.2009.06.09

Yet,it took some time for the team to confirm that the amino acid glycine came from space.

VOA: special.2009.09.30

Then they made small changes to the bacterium's deoxyribonucleic acid -- DNA for short.

VOA: special.2010.07.20

Most of the data comes from the industrialized world. Not surprisingly, burning fossil fuels for transportation and electrical generation top the list for their contributions to climate change, acid rain and toxic pollution.

VOA: standard.2010.06.04

I wrote this son, my father and I wrote this song, for the acid victims of Kandahar City -- a few young girls who were trying to make their way home from school when they got attacked by acid.

VOA: standard.2010.03.08