They have introduced a new system whereby all employees must undergo regular training .

타미교수님 whereby를 사전에서 찾아보니

by which같이 쓰여서 꼭 관계사처럼 쓰인다고 나와있는데

품사는 부사라고 되어있어요.. 용례를 외울수밖에 없나요?ㅠ

He went purple , whereby I saw that he was offended.

여기서 whereby를 관계사로 본다면 선행사는 앞절전체라고

생각하면 될런지요~????