1. If the sound system hadn't failed, last night's show would have been better.
a. this is a correct sentence using the 2nd conditional form
b. this is a sentence using the 3rd conditional form
Answer a.
3. if the club's manager agrees, they'll play a few more original songs next time
a. this is correct using the 1st conditional form
b. this is correct using the 3rd conditional form
Answer a
4. The duo could perform at weddings if Mike played the flute
a. this is correct using the 1st conditional form
b. this is correct using the 3rd conditional form
Answer b
1 is wrong. The other two are right.
http://www.englishclub.com/grammar/verbs-conditional_4.htm
I'm sorry, but your answers are incorrect. Let me explain the correct answers to you.
1. "If the sound system hadn't failed, last night's show would have been better."
- Answer: b. This is a sentence using the 3rd conditional form.
Explanation: The sentence is talking about a past event that did not happen (the sound system not failing). In the 3rd conditional, we use the past perfect tense in the if-clause (If the sound system hadn't failed) and the present perfect tense with "would have" in the main clause (the show would have been better).
3. "If the club's manager agrees, they'll play a few more original songs next time."
- Answer: a. This is correct using the 1st conditional form.
Explanation: The sentence is talking about a possible event or situation in the future. In the 1st conditional, we use the simple present tense in the if-clause (If the club's manager agrees) and the future tense with "will" in the main clause (they'll play a few more original songs next time).
4. "The duo could perform at weddings if Mike played the flute."
- Answer: a. This is correct using the 1st conditional form.
Explanation: The sentence is talking about a possible condition and its possible result in the future. In the 1st conditional, we use the simple present tense in the if-clause (if Mike played the flute) and "could" in the main clause to indicate a possibility (The duo could perform at weddings).