on one's toes

Prepositional phrase

 * 1)  Attentive, active, busy or alert.
 * I keep my students on their toes with pop quizzes.

Translations

 * Chinese:
 * Mandarin:
 * Finnish: varpaillaan
 * German: auf Trab
 * Norwegian:
 * Nynorsk: på tå hev
 * Russian:, , в тонусе