问题
选择题
He was busy preparing his lessons, only _________ occasionally to have some tea.[ ]
A. to stop
B. having stopped
C. to have stopped
D. stopping
答案
答案:D
He was busy preparing his lessons, only _________ occasionally to have some tea.[ ]
A. to stop
B. having stopped
C. to have stopped
D. stopping
答案:D