1. She was entering the subway. At that thie, the dog felt that his old master is near. "On the subway", he barked loudly. People sitting on their seats were surprised.
(Is the expression in the quotation marks correct? Which expression do we have to use? Do we put 'train' at the back?)
2. On the subway
3. In the subway
4. On the subway train
5. In the subway train
She was entering the subway. At that time, the dog felt that his old master was near. "On the subway," he barked loudly. People sitting nearby were surprised.
If you say or write "on the subway," you don't need to add the word "train."
The correct expression to use in this context would be "On the subway". The phrase "On the subway" means that someone is currently on or inside the subway system or train. It is the most commonly used expression when referring to traveling or being inside a subway system.
In this case, the dog sensed that his old master was near while she was entering the subway. He barked loudly, causing surprise among the people who were sitting on their seats. Since they were inside the subway system or train, the correct expression to use is "On the subway".
Therefore, option 2, "On the subway", is the correct choice. Option 3, "In the subway", could also be used, but it emphasizes being inside the subway rather than specifically being on the train itself. Options 4 and 5, "On the subway train" and "In the subway train", respectively, are less common expressions, but they could still be used to convey the same meaning.