Вопрос школьника
Underline the correct item.
1 How long had you been waiting before the bus arrived?
2 Pam went out with her friends after she had finished her homework.
3 We couldn’t leave the lab until we had cleaned the culture plates first.
4 I lost my keys as I was walking home.
Ответ от учителя
1. The correct item is «How long had you been waiting before the bus arrived?» This is the correct sentence structure for asking about the duration of an action that occurred before another action in the past. The past perfect tense «had been waiting» is used to indicate that the waiting occurred before the arrival of the bus.
2. The correct item is «Pam went out with her friends after she had finished her homework.» This is the correct sentence structure for indicating that one action occurred after another action in the past. The past perfect tense «had finished» is used to indicate that the homework was completed before Pam went out with her friends.
3. The correct item is «We couldn’t leave the lab until we had cleaned the culture plates first.» This is the correct sentence structure for indicating that one action had to be completed before another action could occur. The past perfect tense «had cleaned» is used to indicate that the cleaning of the culture plates occurred before the action of leaving the lab.
4. The correct item is «I lost my keys as I was walking home.» This is the correct sentence structure for indicating that two actions occurred simultaneously in the past. The past continuous tense «was walking» is used to indicate that the action of walking was ongoing when the action of losing the keys occurred.
