Whatever I cook, he finds fault with. You don’t need the final “it”.

Physical exercise is essential for good health. You can keep your weight low, your mind young, and your mood happy.

You can use both on and in. 😊

You can use both

Hi Kenya, I offer speaking classes to help students master pronunciation, conversation skills, natural grammar and word choice, as well as situational English. I give real time corrections during class as well as written feedback after the lesson. I’m a native speaker with over ten years teaching experience. (I’ve also just started learning Spanish, but I’m not very good yet 😅) If you’d like to know more then please have a look at my profile and book a trial lesson if it looks like something you’d be interested in. All the best in your English learning journey! Anna

Hi Sonja, I offer speaking classes to help students master pronunciation, conversation skills, natural grammar and word choice, as well as situational English. I’m a native speaker with over ten years teaching experience. (I’ve also just started learning Spanish, but I’m not very good yet 😅) If you’d like to know more then please have a look at my profile and book a trial lesson if it looks like something you’d be interested in. All the best in your English learning journey! Anna

Today the weather is cold because it is winter.

2 and 4 are correct. The others are unnatural and grammatically incorrect.