教室里怎么（这么）安静，原来人多走了。 怪不得他汉语说得怎么（这么）好，原来他妈妈是中国人。 1,in these sentences ,"原来"means "turn out to be"结果是..... 原来我也想去的，因为有事儿没去成. 这儿原来交通恨(很)不方便，现在通了火车方便多了。 2,in these sentences ,"原来"mean "first"开始的时候,从前

原來 有二種意義 1 剛開始時，本來。 (original. former. originally. formerly. at first) 如：「這幢房子經整修後，比原來的模樣好看多了。」 你的 原来我也想去的，因为有事儿没去成. 这儿原来交通恨 (正確: 很) 不方便，现在通了火车 (正確: 火車通了，) 方便多了。 適用本義 這裡的 原來 = 原先 = 原本 = 本來 2 連詞，推究事情本源的口氣。 (so, actually, as it turns out, in fact) 如：「原來那人不是別人，是你呀。」 「我說是誰耽誤了行程，原來是你。」 您的 教室里怎 (正確: 這) 么安静，原来人多 (正確 : 都) 走了。 怪不得他汉语说得怎 (正確: 這) 么好，原来他妈妈是中国人。 適用本義

原来in your first two sentences are used to say that you are not surprised by something, I think people tend to use NO WONDER to express the same thing in English. (I can't think of any other English equalents at the moment. I'm afraid that there's no word for that in English.) 教室里怎么安静，原来人多走了。No wonder it's so quiet here, they're all gone. 怪不得他汉语说得怎么好，原来他妈妈是中国人。No wonder his Chinese is so good, his mother is Chinese. 原来 has a different meaning in your last two sentences, we use 原来 to talk about the situation before things changed or before other things happened. 原来我也想去的，因为有事儿没去成. I wanted to go, but something came up, so i didn't go. (原来 implies that your plan changed. ) 这儿原来交通恨不方便，现在通了火车方便多了。the traffic was bad here, but now it's been improved since train lines came through this area。 （原来 implies that the traffic changed.） 我原来是工程师，现在是医生。I used to be an engineer, but now I am a doctor.（原来 implies that you changed your career.） 它原来是白的，现在是粉色了。it was white, it is pink now.（原来 implies that the color has been changed.）

here in means....actually, as it turns out, in fact) but accept 原來我找你去。。。。 in here in means at first. at the beginning ...

原来-------- -the real reason; the truth; before. 教室里怎么这么安静，原来人都走了-------why is the class so quiet? It's a reason that all of people gone,(原来 a real reason) 怪不得他汉语说得这么好，原来他妈妈是中国人------原来（because,the real reason） the two sentences原来我也想去的，因为有事儿没去成. 这儿原来交通恨(很)不方便，现在通了火车方便多了。 原来（repesent before, in advance, etc) something happened in past time.