有英文句子問題想問問

Wrong.
It should be "Mary had not wash dishes from 7:00 to 8:00 last night."

Did not -> a short period of time
Had not -> a long period of time / duration (e.g. 7-8pm)

agree with karamel

Mary did not wash dishes from 19:00-20:00 last night.
Wendy must tell us more about what happened?
Sometimes too much, sometimes too little posting information ???????
(1)She bought washing-soda.
(2)She repaired the power driven washing machine from 7:00 to 8:00.superfluous more than was needed.

grammer 方面應該冇錯

個人覺得 'from 7:00 to 8:00' 呢句有D多餘,但如在整篇文有用就冇野啦