Choose the correct answer (a, b or c) to complete each gap in the conversation (16–20). A Do you know if the new projector has arrived yet?
B I’m afraid it hasn’t. If it doesn’t come by tomorrow, 16 call the supplier.
A Thanks. Please tell them I need it urgently by Friday. If it 17 arrive by then, I won’t be able to give my presentation. It wouldn’t be a problem if we 18 a spare one, but we haven’t.
B Don’t worry. This is a very reliable supplier. I’m sure they 19 tell us if there was a problem.
A If it was our old supplier, you 20 be so confident.
16 a) I’ll b) I’d c) I
17 a) won’t b) doesn’t c) wouldn’t
18 a) have b) had c) would have
19 a) will b) would c) –
20 a) wasn’t b) won’t c) wouldn’t

16 - a) I'll
This is the correct answer because the person speaking is suggesting that if the projector doesn't arrive by tomorrow, they will take action and call the supplier. The future tense "I'll" is used to express their willingness to make the call.

17 - b) doesn't
This is the correct answer because the person speaking is talking about the possibility of the projector not arriving by Friday. They are using the present simple tense to express a general fact or something that is true now. The correct form to use with "it" is "doesn't" which is the third person singular form of the present simple tense of the verb "to do."

18 - a) have
This is the correct answer because the person speaking is talking about the lack of a spare projector. They are referring to a current situation where they don't have a spare projector. The correct form to use here is "have" which is the present simple tense of the verb "to have."

19 - c) – (no answer)
This is the correct choice because the person speaking is suggesting that the reliable supplier would inform them if there was a problem. They are not using a verb form to complete the sentence, so the correct choice is to leave it blank ("-").

20 - b) won't
This is the correct answer because the person speaking is contrasting the current reliable supplier with the old supplier. They are suggesting that if it was the old supplier, the person they are speaking to would not be as confident. The correct form to use here is "won't" which is the contraction of "will not," indicating a future negative action or state.