问题补充：
. — I sent him the dictionary by mail this morning .
—You that; he\s coming tomorrow afternoon .
A. needn\t have done
B. didn\t have to
C. needn\t do
D. mustn\t do
答案：
(答案→)A. needn\t have done
B. didn\t have to
C. needn\t do
D. mustn\t do
解析：表示“不必做某事但事实上已做了，”应用“needn\t +不定式的完成式”
