Complete the conditional sentences with the suitable parts and identify the types of conditionals. There are no mixed conditionals in this task.

Choose the correct option.

[If you study harder|If you studied harder|If you had studied harder], you would get better grades. — It's the [zero conditional|first conditional|second conditional|third conditional].

Unless you finish your work on time, [you will miss the deadline|you would miss the deadline|you would have missed the deadline]. — It's the [zero conditional|first conditional|second conditional|third conditional].

They wouldn't have been stuck in traffic [if they take the train|if they took the train|if they had taken the train]. — It's the [zero conditional|first conditional|second conditional|third conditional].

If you heat water to 100 degrees Celsius, [it boils|it would boil|it would have boiled]. — It's the [zero conditional|first conditional|second conditional|third conditional].