问题
选择题
He was so busy ____ his homework that he forgot to have supper.
A．to do
B．do
C．doing
D．does
答案
答案：C
题目分析：句意：他总是忙着做功课，以至于忘记吃晚饭。be busy doing sth忙于做某事，固定句型，故选C
点评：be busy doing sth="be" busy with sth 忙于做某事，初中英语对此类固定句型的题目考察较多，对于此类句型平时遇到了要加强积累并加强记忆。