千葉修司 (2018)『英語の時制の一致 時制の一致と「仮定法の伝播」』開拓社，東京。
p. 57-58
補文動詞が状態動詞の時は同時読み（時制の一致読み）がある。
John heard that Mary was pregnant. heard=was
You knew that I was upset about the results. knew=was
I heard that Sally was in London. heard=was
補文動詞が状態動詞でない場合は同時読み（時制の一致読み）がない。
Mary found out that John failed the test. found out > failed
The gardener said that the roses died. said > died
Sally thought that John drank the beer. thought > drank
