I was doing my homework at 9 o'clock last Sunday evening.

2. It means that one action is in progress and another action is also in progress.

I was reading while he was sweeping the floor.

This means that while one action is in progress, another action has already happened.

He was playing while I was studying.

4. Indicate actions that will happen in the past.

She told us that Mr. Li would arrive here.

Mary got her clothes dirty when she cut her finger.

A. manufacturing, manufacturing.

Answer C. Cutting your finger is something that has happened. Use the past tense. At the same time, when expressing the simultaneity of time, "Mary is making clothes" provides the background of what happened, so the past continuous tense is used.

Grandma fell asleep while reading the newspaper.

A. reading; Reading; Phil C. is reading; It was read by Luo Ting; fall

The answer is B. as = when, which means "when" in the sentence. When describing the background of the event, the past tense; When a long action occurs, another short action occurs. Grandma fell asleep while reading the newspaper. Fell (past tense of fall) in a sentence is a copula followed by an adjective, such as fall sick. The basic usage of the past continuous tense: it means that a continuous action was carried out at a certain moment or time in the past, and there is often an adverbial of time in the sentence to indicate this specific time. What were they doing just now? What were they doing just now?

structure

1. Past/present.

At 6 o'clock yesterday afternoon, my mother was cooking. (direct expression)

Contact while

While I was doing housework, my mother was cooking.

3. When means

I was doing my homework when my mother came in. (indirectly indicating the specific time)

We were watching TV from seven to nine last night. We were watching TV from seven to nine last night. What did he study all day last Sunday? What did he study all day last Sunday?