Present Tense 1
Two things about this skill set: 1. It always comes up as needing to be strengthened. No matter how many times, or how successfully, I complete this it say it needs to be strengthened and will not gild. 2. Fine. You like Monday and you don't like Friday. I don't like that out of seventeen exercises in the lesson twelve or more are one of these two sentences. I know repetition is necessary for learning, but come on.
If you read the forum, you will see that this comes up fairly frequently.
Supposedly, repeating the single lesson inside the skill (rather than strengthening the skill as a whole) will work.
What browser are you using? I have just completed Present Tense 1 and 2 without any problems and both are now gold!
Firefox, but I don't think that is the problem as no other skill set is behaving that way. When I first did the skill set it went gold with no problem. Since then it won't re-gild after strengthening.
Have you tried redoing the lesson instead of strengthening it? There is only one lesson so it just might get you over the glitch.