Lately I've been noticing changes in my children's behaviour, something strange is happining to them. *we often use present perfect continuous with words like "recently" or "lately" Probably you know the gender f your child, so you would use the appropriate pronoun. They is a non-gendered pronoun. 2 Mark the towns on the map that you would like to visit in the near future. It's ok without the "the" but I think it sounds better like this. 3 After the passengers' luggage are loaded into the plane, we start boarding the passengers. Personally, I would end this with "We start boarding." to avoid repetition but it is grammatically correct. Also note the spelling. 4 Drunk passangers are not allowed to get onto the plane. Great work!

I would use ' load onto the plane ' rather than 'into' and the following spelling mistakes " happening // passengers" rather than "happining / passangers" but other than those very small points the English is absolutely perfect, very very good English.