1. The plane... at 4 p.m. (take off)

2. Be careful! You...

(fall)

3. I...

my sister in April. (see)

4. Look at the clouds - it...

in a few minutes. (rain)

5. They...

to London on Friday evening. (fly)

6. Hurry up! The conference...

in 20 minutes. (begin)

7. You're so tired! I...

you with these documents.

(help)

8. This time tomorrow we...

on the beach. I can't wait!

(sit)

9. I think astronauts...

on Mars by the year 2020. (land)

10. I promise I...

all the work by next Saturday. (do)

11. We...

together for 12 years next year. (live)​

1. The plane will take off at 4 p.m.
To determine the correct verb tense, we need to look at the context of the sentence. In this case, the sentence is talking about a future event (the plane taking off), so we use the future tense "will" before the verb "take off."

2. Be careful! You might fall.
In this sentence, we are giving a warning about a possible event (falling). We use the modal verb "might" to express uncertainty or possibility.

3. I saw my sister in April.
The verb "see" is in the past tense because it refers to an action that has already happened. In this case, the speaker saw their sister in the past month of April.

4. Look at the clouds - it will rain in a few minutes.
Here, we are predicting a future event (rain) based on the observation of the clouds. We use the future tense "will" before the verb "rain" to express this prediction.

5. They will fly to London on Friday evening.
Again, we are talking about a future event (flying to London). The future tense "will" is used before the verb "fly" to indicate this future action.

6. Hurry up! The conference will begin in 20 minutes.
We are referring to a future event (the conference beginning) and emphasizing the need for speed. We use the future tense "will" before the verb "begin."

7. You're so tired! I will help you with these documents.
In this sentence, the speaker is assuring the listener that they will assist with the documents. The future tense "will" is used before the verb "help" to express this promise.

8. This time tomorrow we will be sitting on the beach. I can't wait!
The speaker is expressing their excitement about a future event (sitting on the beach). The future tense "will" is used before the verb "sit" to indicate this future action.

9. I think astronauts will land on Mars by the year 2020.
The speaker is expressing their belief or opinion about a future event (astronauts landing on Mars). The future tense "will" is used before the verb "land" to express this prediction.

10. I promise I will do all the work by next Saturday.
The speaker is making a commitment to complete a task (do all the work) by a specific future time (next Saturday). The future tense "will" is used before the verb "do" to indicate this future action.

11. We will have lived together for 12 years next year.
In this sentence, we are talking about an ongoing action (living together) that will continue up to a specific future time (next year). The future tense "will" is used before the verb "live" to indicate this future duration.