begin to do or doing

Ответ от Елена Хлопенко[гуру]
Как Вам уже правильно ответили выше, разница между START TO DO и START DOING something несущественна, и зачастую едва заметна, оба варианта грамматически правильны. Однако, если покопаться, можно заметить некоторые отличия. Вот что удалось найти
1) Первое отличие -
The man started to run. --> but he finished doing so
The man started running.--> and probably is still running.
He started to run before he ran, but once he is running, we say "He has started running". The difference is usually slight, but real:
He has never actually run for public office. The man started to run but did not seem to be able to get all the requisite papers filed in time. [Running does not fit this sentence.]
The man started running back in December, and he still runs every Wednesday night. [Running fits this sentence better than to run.]
2) Ещё один аспект -
http:// www. usingenglish. com/forum /ask-teacher /45606 - difference-between-start-do-start-doing. html (убрать пробелы)
start (v.)
This weak verb can be combined with either a gerund or to plus an infinitive: He started speaking and He started to speak mean the same.
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Note, though, that for some native speakers there is a difference between start to do and start doing:
Start to do - hasn't started yet or is in preparation
Ex:I'll start to do that tomorrow.
Start doing - has started already or is already prepared and ready to start
Ex: I'll start doing that tomorrow.