two-step造句

• This finding was used to develop a two-step concentration procedure for virus in tap water .
  这种现象被发展成为对自来水中病毒的两步浓缩方案。
• The yields of aldehydes produced in this sequential process are comparable to the two-step method .
  用此法制得的醛，其产率与用两步法可制得的产率不相上下。