He was busy writing a story, only ______
题型:选择题
问题:
He was busy writing a story, only ______ once in a while to smoke a cigarette. [ ]
A. to stop
B. stopping
C. to have stopped
D. having stopped
He was busy writing a story, only ______ once in a while to smoke a cigarette. [ ]
A. to stop
B. stopping
C. to have stopped
D. having stopped