Is this sentence active or passive In the depression skilled and unskilled laborers lost jobs?

This is an active sentence.

To find out if this is active or passive find the verb. The verb in this sentence is 'lost'.

The verbs in passive sentences have this form - be verb + past participle.

So a single verb - lost - is not a passive verb phrase.

Another way you can tell if a sentence is passive or active, is ask yourself who or what did the action of the verb? Who lost jobs? The answer is skilled and unskilled labourers. The phrase skilled and unskilled labourers comes before the verb so it is in the subject position - subject + verb. This will tell you this is an active sentence.

In a passive sentence the subject is not given. Or if it is given it is called the agent and is put at the end of the sentence using - by + noun (phrase).

This is a passive sentence:

In the depression jobs were lost.

Or if you want to say who lost the jobs:

In the depression jobs were lost by skilled and unskilled workers.