a. (usually followed by `to') not having the necessary means or skill or know-how
s. (usually followed by `to') lacking necessary physical or mental ability
a. 不能的, 不会的
[法] 无能力的, 无资格的, 没有办法的
1. She was unable to finish her homework on time.
她无法按时完成作业。
2. I am unable to attend the meeting because of a family commitment.
我因为家庭事务无法参加会议。
3. The phone was unable to connect to the internet.
手机无法连接到互联网。