"The skilled doctor cured the Ferengi quickly."
Translation:nom verengan vor Qel po'.
Therein lies a great debate. I'll give you my side of it. Sorry for the long-windedness of it.
Short answer: yes, either vorta' or vorpu', for the obvious interpretation of this sentence: an event occurs in which a doctor quickly cures a bunch of Ferengi. The reason: the sentence is being delivered from the viewpoint a time when the curing is already complete. It is describing an entire action, the curing, from beginning to end. Including the endpoint, it is "completed." This is perfective aspect. It's not past tense; it's a completed action. In Klingon, when you're describing a completed action, a perfective suffix is required.
Without the perfective suffix, this sentence means The skilled doctor cures the Ferengi quickly. It's given from the viewpoint of being in the moment of curing (whether that moment is quick or takes a long time; it doesn't matter). The action of curing is not yet complete. "The absence of a Type 7 suffix usually means that the action is not completed and is not continuous (that is, it is not one of the things indicated by the Type 7 suffixes)." (The Klingon Dictionary)
Notice that nom verenganpu' vorpu' Qel means both The doctor cured the Ferengi quickly and The doctor will have cured the Ferengi quickly. Without a time context of some kind, a Klingon sentence does not specify whether it occurs in the past or future. (But it isn't happening in the present, because then the curing would not yet be complete, and the perfective suffix would not be allowed).
So why isn't the course doing this? Because for many years the conventional wisdom of Klingonists, mostly in the Klingon Language Institute, was that the perfective suffixes mean something was done "before the time context." If the time context were yesterday, then using perfective would mean the action occurred before yesterday. This is what I used to think, just like everyone else. Over the years I started noticing instances where Okrand would come out with a sentence that didn't match that idea. I delved into the concept of perfective more, and even asked Okrand about Klingon perfective. I figured out how it works.
Convincing everyone else, though, is an uphill task. They're quite set on the "before the time context" idea, even though "before" is a tense concept, and Klingon verbs have no tense. And they don't want to hear that they've been doing it wrong for decades.
So throughout this course, perfective will be treated wrong. You're going to come across dozens of sentences just like this one that are obviously perfective in meaning, but which don't allow you to use a perfective suffix in the Klingon.
The course creators have a little wiggle room for some of these sentences. In this one, for instance, it seems obvious that The doctor cured the Ferengi quickly refers to an event in which a cure was applied. That's perfective. But it could conceivably be used in a situation in which the doctor regularly treats Ferengi, and always does it quickly. In that case, it's not perfective, and no Klingon perfective suffix should be used. So the course answer is not technically wrong, if you interpret the sentence that way. But it should allow the perfective interpretation too, and it probably doesn't. And there are other sentences in the course that are definitely perfective in meaning, with no obvious non-perfective use, which don't allow Klingon perfective.
So the best we can do at this point is tolerate the problem in the course and try to explain to people that the course is teaching perfective wrong.