alertness [ə'lɜ:tnəs]

例句:

• The drug improved mental alertness.
  该药有助于提神。
  
• Alertness, calmness, courage : he could see them all in the youngster's face.
  机警, 镇定, 胆量,都摆出在这年青人的脸上.
  
• We must maintain a military standard, an alertness, and never vary it.
  我们必须保持军队的准则, 应当随时注意,切勿随时变动.
  
• Rivers, who drifted in and out of alertness.
  来自WSJ
• The tiny station was in the midst of its...half-hour of alertness.
  来自J. Wain
• Resisting the urge for a lie-in can pay dividends in alertness.
  来自BBC