Translation:That advertisement is funny!
If I remember correctly this was addressed in one of the earlier skill's tips and notes section, but generally in this course it is translated without the very, which is why I find 真好笑 better than 很好笑
In this case 很 is needed because the sentence would be grammatically incorrect without it, so it doesn't really mean "very" here.
"That advertisement is funny!" is acceptable, as is the same sentence with "ad," but not "advert." Where's the sense in that?
The people making the course are probably just more familiar with American English than British English.