问题
选择题
The professor _______ to walk out of the office when one of his students came in.
A．was about to
B．was going to
C．would
D．was to
答案
答案：A
考察固定句式be about to，将要做某事。句意：当他的一位学生进来时，这位教授即将走出他的办公室。选项BCD缺少谓语动词，故选A。