An acquaintance of mine recommended this video. It is filled with lots and lots of grammatical mistakes. I am sure that the makers of this video had good intentions, so I don't want to be too harsh.
It's a bit of a pity, if they had proofread their work before posting it on youtube, it would have been a much better resource. A lot of work has gone into the graphics and presentation.

So rather than learn mistakes, let's turn this into a useful resource. What I'd like you to do is find the mistakes in this video and say what is wrong in each case. That way, hopefully some good might come from this.
Please post your answers below.
The video is below this sentence.

I haven't put the mistakes in order of when they occur in the video, nor have I listed all of the mistakes.

1 There should not be a space before the comma.

2 If Luisa had gone with us, she would have had a great time.

3 If I hadn't eaten so much, I wouldn't have gotten a stomach ache.