These words can be used both as prepositions and conjunctions. They mean exactly the same. Till is mainly used in informal English. We use until to talk about a situation or state that will continue up to a certain moment.

Tenses after till / until

After till and until we use present tenses to refer to the future.

• Please wait here until I come back. (NOT Please wait here until I will come back.)
• You are not going home until you finish that report. (NOT You are not going home until you will finish that report.)

Combine the following pairs of sentences using until.

1. Please wait. I’ll finish my homework.

2. I’m busy. I’ll be free only after 5 o’clock.

3. You must not leave the room. I will let you go.

4. They went on shouting. The manager agreed to look into the matter.

5. The doctor told her not to worry about her husband’s health. Only then was she relieved.

Answers

1. Please wait until I finish my homework.

2. I’m busy until 5 o’clock. / I’ll not be free until 5 o’clock.

3. You must not leave the room until I let you go.

4. They went on shouting until the manager agreed to look into the matter.

5. She was not relieved until the doctor told her not to worry about her husband’s health.