Happy April Fool's Day!!!!!!!!!!!!! Happy April Fool's Day!!!!!!!!!!!!!

i am so confused of at ,in ,on ,to ,for ,of,etc. Preposition is so difficult to me to use.who can give me some examples .thank you a lot!!!!

网上聊天英语都常用哪些句子啊？比如汉语常用：你好！看到了吗？在吗？

what is the best tool to learn english? hello friends from everywhere,who can suggest to me a tool to make me able to commnicate easier.