Use will or going to and one of the verbs below. drive forget have visit
1a. Are you late? I
you to the bus stop if you want.
1b. Next summer my cousin
across America with his girlfriend
2a. We
my grandparents this weekend.
26. I think astronauts
other planets in the next twenty years.
3a. Tea or coffee?? I
coffee, please.
3b. You've been in the sun for hours. You
terrible sunburn.
4a. I
(not) your birthday again this year. I promise!
4b. Dad's so busy. He
his and Mum's wedding anniversary again.​

1a. Are you late? I will drive you to the bus stop if you want.
To answer this question, we need to decide whether the action of driving to the bus stop is a spontaneous decision or a planned arrangement. Since it is conditional on the person being late, it is more likely a spontaneous decision. Therefore, we use "will."

1b. Next summer my cousin is going to drive across America with his girlfriend.
Here, we are talking about a planned arrangement for the future, which is driving across America. It is something that has been decided and is intended to happen. Therefore, we use "is going to."

2a. We are going to have a visit to my grandparents this weekend.
Here, we are talking about a planned visit to the grandparents. It is something that has been arranged in advance. Therefore, we use "are going to."

2b. I think astronauts will visit other planets in the next twenty years.
This sentence expresses a prediction about the future. It mentions what the speaker believes will happen in the next twenty years. Therefore, we use "will."

3a. Tea or coffee? I will have coffee, please.
This sentence expresses a spontaneous decision regarding the choice of drink. The person didn't have a pre-planned intention to have coffee, but rather decided in the moment. Therefore, we use "will."

3b. You've been in the sun for hours. You are going to have a terrible sunburn.
Here, we are talking about a consequence that is likely to happen as a result of the person being in the sun for a long time. It is something that is expected to happen. Therefore, we use "are going to."

4a. I won't forget your birthday again this year. I promise!
This sentence expresses a negative intention for the future. The person is making a commitment to remember the birthday and not forget it. Therefore, we use "won't" (will not).

4b. Dad's so busy. He will forget his and Mum's wedding anniversary again.
Here, we are talking about a future event that is likely to happen based on the father's busy schedule. It is something that is predicted to happen. Therefore, we use "will."