(i) Imagine that Margie’s mother told her, “You’ll feel awful if you don’t finish your history lesson.”

(ii) She could also say: “you’ll feel awful unless you finish your history lesson.”

Unless means if not. Sentences with unless or if not are negative conditional sentences.

Notice that these sentences have two parts. The part that begins with if not or unless tells us the condition. This part has a verb in the present tense (look at the verbs don’t finish, finish in the sentences no (i) and (ii) above).

The other part of the sentence tells us about a possible result. It tells us what will happen (if something else doesn’t happen).The verb in this part of the sentence is in the future tense (you’ll feel/ you will feel.)

Notice these two tense again in the following examples:

(Future Tense)		(Present Tense)
1. There won’t be any books left	unless	we preserve them.
2. You won’t learn your lessons	if	you don’t study regularly.
3. Tommy will have an accident	unless	he drives more slowly.

Complete the following conditional sentences. Use the correct form of the verb.

(i) If I don’t go to Anu’s party tonight, ____________.

(ii) If you don’t telephone the hotel to order food, _________.

(iii) Unless you promise to write back, I __________.

(iv) If she doesn’t play any games, ______________.

(v) Unless that little bird flies away quickly, the cat____________.