Expressing "no wonder"
怪不得 (guàibude) can be used to express that the speaker finds something unsurprising. It can be used alone or in a variety of different structures, as shown below. 难怪 (nánguài) is another way to express exactly the same thing.
Emphasis on 怪不得
怪不得 is used to convey the speaker's lack of amazement at a situation, having recently acquired some new information that in his opinion explains it. It can be replaced with 难怪 in the structure without altering its meaning.
Reason ，怪不得 / 难怪 + [Observation]
- 小张 请假 了，怪不得 今天 没有 看到 他 。Little Zhang asked for some vacation time, no wonder I haven't seen him today.
- 天天 迟到 ，怪不得 他 被 炒鱿鱼 。He's late for work everyday. No wonder he got fired.
- 她 是 你 妹妹 ？难怪 你们 长 得 这么 像 。She's your younger sister. No wonder you two look so much alike.
- 你 手机 没电 了 ？怪不得 我 打 不 通 。Your cell phone is out of battery? No wonder I couldn't get through.
- 你 放 了 醋 ？难怪 这么 难吃 ！You put vinegar. No wonder it taste so bad!
Emphasis on 原来
怪不得 / 难怪 + [Observation] ，原来 (+ 是) + Reason
- 怪不得 她 拉肚子 ，原来 她 昨天 又 吃 火锅 了 。No wonder she had a diarrhea. She went to eat hotpot again yesterday.
- 难怪 学生 都 不 喜欢 这个 老师 ，原来 他 的 作业 太 多 了 。No wonder the students don't like this teacher. The homework he gives is too much.
- 怪不得 你们 这么 高兴 ，原来 是 要 结婚 了 。No wonder you two look so happy. You are getting married.
- 难怪 这里 人 这么 多 ，原来 在 打折 。No wonder there are so many people here. There's a sale going on.
- 怪不得 他 没 告诉 我 ，原来 是 不 想 让 我 担心 。No wonder he hasn't told me. He doesn't want me to worry about this.
the Other Meaning of 难怪
This usage is definitely less common, but sometimes 难怪 is a combination of the 难 + Verb pattern and the verb 怪, meaning "to blame." In this case, the meaning is totally different. Although it's not as common and you shouldn't need to worry about it too much, we include it here because if you ever run into and think that 难怪 can only ever have one meaning, it can totally throw you for a loop.
A few examples:
- 这 也 难怪 他 ，他 这么 小 。Don't blame him. He's so young.
- 这 也 难怪 大家 ，是 我们 通知 晚 了 。Don't blame everybody. It was a short notice.
When used in this way it expresses that the speaker assigns no blame in the situation he is describing. Sometimes the specific person undeserving of blame is mentioned directly after 难怪, as in the first two examples. Often however the context makes clear who this person is and this is not necessary, as in the third example.
Sources and further reading