名詞 alertness:

1. the process of paying close and continuous attention
   同義詞：watchfulness, wakefulness, vigilance
2. a state of readiness to respond
   同義詞：alerting
3. lively attentiveness
   同義詞：sharp-sightedness, on the qui vive

1. Emily is a Londoner born and bred and, for a woman some years past the allotted span, of a truly remarkable vigour and alertness.
   埃米莉生在倫敦長(zhǎng)在倫敦，雖已年逾古稀，但實(shí)在令人驚訝的是，她仍精力充沛，耳聰目明。