Past tenses：练习题

Choose the correct verb form to complete the sentence:
"While the students ______ their research papers in the library, the fire alarm suddenly began to ring."

By the time the police arrived at the scene, the suspects ____ for several hours through the dense forest, leaving behind a trail of evidence.

While the students ____ their final chemistry exams, the power suddenly went out throughout the whole building.

We ____ to visit the museum last Saturday, but we changed our minds when we saw the length of the queue.

Identify the correct sequence of past events:
"By the time the rescue team finally ______ the remote village, the floodwaters ______ significantly."

Complete the sentence with the correct past tense form of the verb in brackets to show an action that was in progress when it was interrupted:
"While Sarah ______ (read) the textbook, her computer suddenly crashed."

Complete the sentence using the past perfect continuous tense to show an action that was in progress until another event occurred:
"The athletes ________ (train) for three hours before it started to rain heavily."

Explain the difference in meaning between these pairs of sentences involving past tenses and structures:

a) I used to live in London. / I was living in London when I met him.
b) When the guests arrived, my mother made dinner. / When the guests arrived, my mother had made dinner.
c) I had my hair cut. / I cut my hair.

Read the paragraph below and put the verbs in brackets into the correct past tenses (Past Simple, Past Continuous, or Past Perfect).

When I (arrive) at the station, the train (already / leave). I (be) frustrated because I (wait) for ages at the bus stop earlier, which caused my delay. While I (walk) home, I (realize) that I (leave) my umbrella on the platform.