I usually .... at a market in London.
1. have worked
2. am working
3. have been working
4. work

work

Объяснение:

Dear alex,  i was very glad to hear from you again. i haven't written for ages because of my school activities.in your letter you asked me to say a few words about my future profession. i would like to be an account. why? i'll try to explain. nowadays the profession of an account is very important. every office, every organization has got centralized accounting.  in every organization there is a specialist, who should be able to maintain the accounting, inventory, make accounting reports and settlements with suppliers and consumers, calculate profit or anticipate losses, calculated salaries of the stuff and so on.  that is why we need qualified specialists, who are able to carry out necessary and very serious documentation, know the law and many other materials. therefore, a person who works as an accountant must be a very clever, responsible and serious.nowadays many institutions and universities in all countries prepare specialists we call as accountants.  that's all for me today. i have to go to the swimming pool.  best regards to your family.write soon.