문장
I saw a movie in which the villain goes to jail (1)
He has made a mistake with which I am familiar (1)
There were ten apples four of which were rotten (1)
This is the way by which we can achieve our goals (1)
She showed him the hospital at which she was born (1)
New inventions, by which lives are transformed, inspire human progress (1)
This is the school in which I spent three years of my life (1)
It is not an idea around which the community can unite. (1)
This is the river into which they are fallen (1)
Tell me about the project on which they've been working (1)
This is the best explanation of which I got the most benefit (1)
This is the way in which you can solve this problem (1)
Can you identify at which points the problems start reliably (1)
Renewable energy by which (1)
This is the report to which I was referring (1)
The new software with which tasks are (1)
This is the topic about which I planned to write (1)
This is the bed on which I sleep. (1)
It describes the speed at which a planet moves in its orbit. (1)

전치사_관계대명사

(10)
with which

그는 나에게 친숙한 실수를 저질렀어. 나도 아는 실수를 저질렀어

about which

영어의 또 하나의 어려움 중 하나가 전치사 + 관계대명사의 형태이다. 우리 한국인들이 많이 당황하지만 그럴 필요없다. 여기에 형태별로 제시하는 예문을 계속 듣고 따라해보라. 입으로 익혀지고 말이 되고 글이 될 것이다. 해석은 물론 기본적으로 빠른 속도로 뇌에 새겨질 될 것이다.

at which

구체적으로 어디에서 문제가 확실하게 발생했다고 말씀해주시겠어요?