clear head
noun [ C usually singular ] uk/ˌklɪə ˈhed/ us/ˌklɪr ˈhed/
清醒的头脑
the ability to think clearly
I won't have another drink, thanks. I need to have a clear head for my meeting in the morning. 谢谢，我不再喝了。我上午要参加一个会议，得保持头脑清醒。
clear-headed
adjective uk/ˌklɪəˈhed.ɪd/ us/ˌklɪr-/
头脑清醒的
able to think clearly