a. being effective without wasting time or effort or expense
a. 有效率的, 能干的
1. The new software is very efficient and saves a lot of time.
这个新软件非常高效,可以节省很多时间。
2. She found an efficient way to organize her study schedule.
她找到了一个高效的方式来组织她的学习计划。
3. Using public transport is often more efficient than driving a car.
使用公共交通通常比开车更高效。