At that time, the White House was as serene as a resort hotel out of season. The corridors were [1]. In the various offices, [2] gray men in waistcoats talked to one another in low-pitched voices. The only color, or choler, curiously enough, was provided by President Eisenhower himself. Apparently, his [3] was easily set off; he scowled when he [4] the corridors.
Fill in the blank with the correct option.
The teacher believed that the student’s sudden lack of interest in class was an ..........., as he had always been enthusiastic and attentive.