John is the only one of the students in the class who never _____ a mistake even when it is pointed out to him.
On weekends the Smiths usually drive to the countryside and ________ the fresh air there.
In face of the challenge for the moment, it’s most important to ______ a good state of health.
Fully ________ in my office work, I have little time for housework.
Nancy reminded me of what I should ________ have forgotten.
Helen borrowed my book _______, saying that she would return it soon.