Generally speaking, your sentence is right according to the grammar. Bcz, " 的时候"="when"(in a statement,not a question), so you can say anything as you like. This sentence is not the real Chinese way although there is no mistake, because you didn't give us your content or any hint, just a sentence only the grammar is a bit strange, so we have to use the whole sentence structure like"Subject + Verb + Object" is our Chinese way, as a result, all of the people who correct you add an object for the verb "吃", like "吃饭" "吃东西"etc. hope will help you more or less.

There are several kinds of schools that as you said. If you want to learn Chinese as full- time work, I advise you to go to some universities, but if you want to learn Chinese as part- time for example, in the evening, morning ,weekends, or twice of a week, you could choose some language training companies. If you are in Shanghai, you could buy the magacine called "That's Shanghai", you will find many ads. about Chinese training, or you could ask me, because I know the language training market well in Shanghai. Hope you can find one that fits you well. Good luck :-)

Dear friend, Don't worry so much abuot the peoblem, even for me I cannot understand the southen people words somtimes, so don't worry!! When you are not sure you could ask them try to explain it in longer sentence rather than only one or two words, which is the most effecient way I always tell my foreign friends. You will find that is much easier for u to understand within a certain dialogue. Hope it will help you more or less:) Tang

Dear friend, according to my experience Chinese characters are difficult for Westen people, but many of them learnt well. The suggestions as followed: 1. Radicals. Usually I teach my students according to the radicals, because radicals are very very important for learning characters, and each radical has their own meaning. If you manage the radical meanings, you could make guess the characters meaning even you havn't learnt before. They are like prefix and suffix in English, they are the tool which you enlarge your characters vocabulary. You could choose some typical characters of one radical to learn, for example :the radical of warter, then you could learn 江河湖海.... 2. Strokes Order. If you are learning how to write the characters, the important thing is writing order. I met many foreigners who always forget how to write characters even they have learnt many times. The reason is the writing order is not correct, the order they write is as they like but not follow the right order, so it is difficult to remember even for Chineses. 3. Just reading. You could learn how to recognize the characters first, then one year or half year later learn how to write them. 4. Buying a good book. Generally speaking I will choose some good books for my students. Usually they will including how some characters come to today's shape. Because you could know why we write the characters like this but not like that. Most of the students will say "WOW ...interesing! " "Amazing!" then you could find some fun in that. 5. Confidence. Many of foreigners are afraid of learning characters, they always say "I don't want to learn drawing pics", however, we still have many good examples, they learn characters very well!!! You also can do it, NOTHING IS IMPOSSIBLE! JUST DO IT! and you will enjoy it:) Good luck:)