Refer the sentences to the future: 1) What. you buy for your mother as birthday present? I. buy a box...

1) What will you buy for your mother as a birthday present? I will buy a box of sweets. 2) Will you invite Bill to your birthday party? Yes, I will. 3) Nina will not go to school tomorrow. She is ill. 4) Where will we go next month? We will not go to Kiev, we will go to Odessa. 5) When will you do your homework? I will do it at four o'clock.

To refer these sentences to the future, you will need to use the appropriate future tense structures. In English, the future can be expressed in several ways, most commonly with "will" for decisions made at the moment of speaking or for predictions, and "going to" for plans or intentions. Below is a detailed conversion of each sentence to the future tense:

1) What will you buy for your mother as a birthday present?

• This sentence is asking about a future decision or plan regarding a gift, so "will" is appropriate.
• Answer: I will buy a box of sweets.
• Here, "will buy" indicates a future intention or decision.

2) Will you invite Bill to your birthday party?

• This is a yes/no question about a future action, so "will" is used.
• Answer: Yes, I will.
• "Will invite" shows future intent to perform the action.

3) Nina will not go to school tomorrow. She is ill.

• This sentence uses "will not" (often contracted to "won't") to indicate a future action that will not happen due to current circumstances.
• "Will not go" clearly shows a future action that is planned not to happen.

4) Where will we go next month?

• This question is asking about a future plan, so "will" is appropriate.
• Answer: We will not go to Kiev; we will go to Odessa.
• The use of "will go" and "will not go" indicates future intentions or plans.

5) When will you do your homework?

• This is asking for a future time when the action will take place.
• Answer: I will do it at four o'clock.
• "Will do" specifies a future action and the time when it will occur.

In summary, using "will" is a common way to refer sentences to the future in English, especially for decisions, predictions, and actions planned for the future.