Carol's family

1/ "One year" is singular, therefore you have to use the singular form; year, not years.

2/ You move something to, rather than on. However you could also say that she puts them on a higher shelf.

3/ You're not going to like this, but generally the rule of thumb for deciding whether to use an expression like "more high" as opposed to "higher" is the number of syllables in the adjective. If it's a single syllable (high, hot, cold. etc) you would use a form like colder, hotter, higher, older, etc. If it's three or four syllables it's usually "more something"; more intelligent, more careful, more impressive. Where it's two syllables it can go either way; is it "tastier", or is it "more tasty"? You could probably get away with either in that case. Remember that this is a guideline, not a rule of grammar, but it's useful.

Carol's sister is six. A few weeks ago she couldn't swim or go on a bike. Now she goes to swimming classes and can swim a little bit. Carol is teaching her to ride a bike. She can do it in the garden and soon she will be able to go in on the street.

1/ There is always an article ("the" or "a" (or "an")) before words like "few" (as well as words like "couple"), as well as in front of nouns like "bike". (Unless you use a possessive adjective like "her bike").

2/ It would be more common to say "swimming classes" since there will be more than one of them. Saying "class" is not completely wrong, though, and it's not unheard of.

3/ "Bike" is rarely used as a verb, and not in that case; there it would be "ride a bike".

4/ It's also more common to say "on the street" when you're talking about walking or taking a vehicle down it; it's the same as "sulla strada" in Italian.

Carol's grandpa is seventy. A few years ago he could run marathons and playied played tennis. Now he can't do those sports any more (usually two words), but he can do long walking walks and swimming. He still does exercise.

"Walking" is what you do when you go "for a walk". It's like the difference between "camminando" and "fare una passeggiata". You could however also have said "he can do a lot of walking" but "do long walks" (or perhaps better still "go for long walks") works better.

Thanks for your comments on my previous correction; I'll drop you a reply to your question shortly but I need to get a couple of things done before heading to bed. (It's late here, but early there.)

Carol's family

Very well written!