fast/slow in reacting to a situation（对形势）反应敏捷／迟钝- If you’re quick off the mark in answering these questions, you could win a prize.如果你能很快回答这些问题，你就能获奖。
- The government was slow off the mark in responding to the crisis.政府对危机反应迟钝。
See also mark | quick | slow