Более-менее вынужденные артикли для Вас поставил. Если задание заключалось в САМОСТОЯТЕЛЬНОМ нахождении мест для артиклей в предложениях, то ответ, по-моему, должен быть таким:
1.) I don't like reading romantic novels. The romantic novels in read were rather silly.
2.) I hate wearing formal clothes. The formal clothes I wear are always black.
3.) I dislike eating spicy food. But the spicy food I had in India was just to my liking.
4.) They say that European cities are polluted by cars. The cities we visited in Germany weren't polluted, air was fresh and clean.
5.) people usually think that babies are sweet. The babies I took care of were constantly crying.
6.) Sorry I'm late. I took a wrong bus.
7.) A/(-) captain of a ship welcomed passengers on a deck.
8.) We don't know how old the Universe is.
9.) Duke Street? We live in the same street.
10.) The lion is King of jungle through it lives on plain.
11.) An/(-) invention of the wheel was a great step in the development of the transport.
12.) You shouldn't ask questions, if you already know answers.
13.) Paris is the capital of France.
2. This is not my plate
3. Is this your dog?
Вообще задание дано не очень хорошее, "This is not... Is this?" Не говорят. Лучше вместо This поставить It