Let's work on your weakest concept...
Let's work on your weakest concept... and then it doesn't actually make you work on your weakest concept. Today it said we're going to work on the imperative. And while there were imperatives in the prompts, the answer it wants is rarely even the verb, but rather a noun or some other part of speech.
Ponte ___ gorra.
It's looking for esta. And then it'll mark you wrong for answering la.