Learn Spanish (Latin America): No alimentaré al mono herido hasta que llegue el doctor. - I will not feed the injured monkey until the doctor arrives.

The phrase hasta que (until) sets up a time clause. Because the doctor's arrival is a future event that hasn't happened yet at the moment of speaking, Spanish requires the present subjunctive llegue. If you were talking about a habitual event, like saying that you never feed the monkey until the doctor usually arrives, you would use the indicative.

Why does el doctor come after the verb llegue?

In Spanish, it is very common to place the subject after the verb in dependent clauses, especially with verbs of motion, arrival, or existence like llegar. You could say hasta que el doctor llegue, but hasta que llegue el doctor flows much better to a native ear.

Why is there an al before mono herido? Isn't the personal a just for people?

The personal a is mostly for people, but it is also used for specific, individualized animals. Since this is a specific monkey (perhaps a patient or a pet), it gets the personal a. Combined with the masculine article el, it forms the mandatory contraction al.

Is herido a verb or an adjective here?