—Professor, do you have something at this moment?
— No, thanks. I’ll call you if any.
A. to be typed
B. to type
C. typing
D. typed
网友回答
(答案→)A. to be typed
B. to type
C. typing
D. typed
解析：本题易误选B和D。B项的执行者应是secretary而不是professor；动词不定式常与即将完成的动作相联，所以CD错。