alertness的例句（alertness在句子中的用法）

• 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.
• 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.
• The drug improved mental alertness. 该药有助于提神。