-----I stayed up late last night preparing the speech.
----- you look so tired today.
A. No doubt
B. No problem
C. No time
D. No wonder
网友回答
A. No doubt
B. No problem
C. No time
(答案→)D. No wonder
解析：There is no doubtthat…不容怀疑；No problem没问题；No time没时间；It is no wonder that ….难怪，它的省略的形式是No wonder+句子。句意：--我昨天晚上熬夜准备演讲稿了。--难怪你今天看起来那么累。